DHANALAKSHMI COLLEGE OF ENGINEERING, CHENNAI DEPARTMENT OF CIVIL ENGINEERING CE 6403 APPLIED HYDRAULIC ENGINEERING UNIT I: UNIFORM FLOW

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1 DHANALAKSHMI COLLEGE OF ENGINEERING, CHENNAI DEPARTMENT OF CIVIL ENGINEERING CE 6403 APPLIED HYDRAULIC ENGINEERING UNIT I: UNIFORM FLOW PART A (2 marks) 1. Distinguish between open channel flow and conduit flow. (N-13) S.No Closed conduit flow Open channel flow 1. Water does not have with free surface. 2. Water does not contact with atmosphere pressure but it has only hydraulic pressure. 3. Flow may be due to either by pump pressure or by gravity flow Water flows with a free surface. Water contents with atmospheric pressure. Flow is obtained only by gravity. 2. What are wide open channels? Channels with large aspect ratio (b/y) is called wide open channel. Otherwise width of channel is too large by comparing its depth is called wide open channel. 3. Define open channel flow? (N-13) Flow of liquid with a free surface (i.e., surface exposed to atmosphere) through any passage is known as open channel flow. The liquid flowing through any closed passage without touching the top can also treated as open channels. 4. Compute the hydraulic mean depth of a small channel 1m wide, 0.5m deep with water flowing at 2m/s. Hydraulic Depth D=cross sectional area of flow/ top width = 0.5*2/2 = 0.5m 5. Define Specific energy of flowing liquid. (A-12) Specific energy of a flowing liquid is defined as energy per unit weight of a liquid with respect to the bottom of the channel. It is represented by a symbol E. y-depth of the flow V-depth of the flow 6. How do you find the critical depth of flowing water? (N-11) Depth of flow of water at which the specific energy E is minimum is called as critical depth (yc). For rectangular channel, critical depth,

2 7. What are the different types of flow in open channel? (N-11) The flow in open channel is classified into the following types: a) Steady and unsteady flow b) Uniform and non- uniform flow c) Laminar and turbulent flow d) Subcritical, critical and supercritical flow. 8. In an open channel of rectangular section if the minimum specific energy is 6 m, what is its critical depth? Given:Emin= 6m Emin= 3/2yc 6 = 3/2 yc Critical depthyc = (6*2)/3 = 4m 9. A rectangular channel carries a flow of 4m 3 /s/m, what is the critical depth? Critical depth yc= (q 2 /g) 1/3 Where discharge per meter width = q = 4m 3 /s/m yc = (4 2 /9.81) 1/3 = 1.177m 10. What are the different types of varied flows? 1. Gradually varied flow If the depth of flow changes gradually over a long length of the channel, the flow is said to gradually varied flow (GVF). 2. Rapidly varied flow. If the depth of flow changes rapidly over a small length of the channel, the flow is said to be rapidly varied flow. 11. Define hydraulic depth (D) of an open channel flow. D=hydraulic depth in m = = 12. Give the Manning s formula. Where, V= velocity of flow N = Manning s constant R =Hydraulic radius or hydraulic mean depth = area/perimeter=a/p S =slope of the channel 13. What are the essential conditions for most economical section? (N-07) A section of the channel is said to be most economical when the cost of construction of the channel is minimum. But the cost of construction mainly depend up on the excavation and lining to keep the cost minimum,the wetted perimeter for a given discharge should be minimum.

3 14. Write down the Chezy s formula for determining velocity of flow in an open Channel V=C Where C = Chezy s constant R = A/P = Hydraulic Radius S = Slope of the channel bed. 15. Show that the maximization of discharge requires minimization of the wetted perimeter of the channel for a given area of flow. (A-13) For a given channel slope, roughness coefficient and area of flow, the maximum discharge of channel is obtained when the wetted perimeter is minimum. For wetted perimeter (P) to be minimum, dp/dy=0 If second derivative of P is positive, the condition of minimum P is obtained. 16. Distinguish between uniform and non-uniform flow. (A-08) If the depth of flow, slope of the bed of channel and cross section remain constant with respect to distance is called uniform flow. Flow properties, such as depth of flow, velocity of flow are not constant with respect to distance is called non uniform flow. 17. Define the Froude Number. What is its significance? Froude Number <1 Where V = Average velocity of flow in m/s g = Acceleration due to gravity =9.81 m / s 2 D = Hydraulic depth in meter =Cross Section Area of flow /Top Width = A/T 18. Distinguish between normal depth and critical depth. Normal depth is the depth of flow for a channel geometry, slope, roughness and a specified value of discharge, a unique value of depth occurs in a steady, uniform flow. It is denoted by the symbol yo. The normal depth is used to design artificial channels in a steady, uniform flow and is computed from Manning s equation. Critical depth is defined as the depth of flow of water at which the specific energy E is minimum. From Specific Energy curve corresponding to the minimum specific energy E there is only one depth of flow that is called Critical depth (yc). 19. What are the conditions for the most economical trapezoidal channel section? 1. Half the top width is equal to one of sloping side (b+2 nd)/2=d (1+n2) 2. Hydraulic mean depth is equal to half the depth. 20. Why are best hydraulic sections in open channel flow referred as most economical sections? Most economical section is also called as best hydraulic sections as the discharge passing through a most economical section of channel for a given cross sectional area (A), slope of the bed (i) and a resistance coefficient is maximum.

4 21. A river with a lined banks has a Manning s n = 0.014, and Chezy C = 55, what is its hydraulic radius? C = 1/n *R 1/6 55 = 1/0.014 *R 1/6 R 1/6 = * 55 = 0.77 R = = 0.208m 22. Define uniform flow. Uniform flow is a fluid flow in which the velocity of any given instant does not change both in magnitude and direction with respect to space Mathematically, 23. What are the geometric conditions for a triangular channel to be most economic? If the triangular channel is most economic when the side slopes are 1Vertical: 1 Horizontal or the side slope at 45º with the vertical. 24. Define specific force (Fc). Specific force is the sum of the pressure force (F) and momentum force due to flow (M) per unit weight of the liquid at a section. 25. Define alternative depth? In the open-channel flow of rectangular channels, the alternate depth equation relates the upstream (y1) and downstream (y2) steady-state flow depths of a flow that encounters a control device, such as a sluice gate, which conserves energy for a given discharge.

5 PART- B (16 marks) 1. A trapezoidal channel with side slope of 2H: 3H has to carry 20m 3 /s. Find the slope of the channel when the bottom width of the channel is 4m and depth of water is 3m. Take manning s n = (M-13) 2. Calculate the specific energy of 12m 3 /s of water flowing with a velocity of 1.5m/s in a rectangular channel of 7.5m wide. Find the depth of water in the channel when the specific energy would be minimum. What would be the value of critical velocity as well as minimum specific energy? 3. Determine the critical depth for a specific energy of 1.6m in rectangular, triangular and trapezoidal channels. (N-13) 4. Determine the critical depth and specific energy for a discharge of 5m 3 /s for a trapezoidal channel. The bed width of channel is 2.1m and the side slope is 1V:1.5H. (N-14) 5. A 8m wide channel conveys 15cumecs of water at a depth of 1.2m. Determine a) Specific energy b) Critical depth, velocity & minimum specific energy c) Froude number & type of flow 6. In flow through a rectangular channel for a certain discharge the Froude s number corresponding two alternate depths of F1& F2. Show that (F2/F1) = (2+F2 2 )/(2+F1 2 ) (M-15) 7. Calculate the specific energy, critical depth and velocity for flow of 10m 2 /s in a cement lined rectangular channel 2.5m wide with 2m depth. Is the flow sub/super critical? (M-16) 8. A trapezoidal channel has a bottom width of 6.1m & side slope of 2H: 1V. When the depth of flow is 1.07m, the flow is 10.47m 3 /s. What is the specific energy of flow? Is the flow tranquil? 9. A channel is designed to carry a discharge of 20 m 3 /s with manning s n = and bed slope of 1 in 1000 for a trapezoidal channel side slope m = 1 / (3) 1/2. Find the channel dimensions for the most efficient section if the channel is a) Trapezoidal b) Rectangular 10. Explain the various types of flow in an open channel. Also draw and explain specific energy curve.

6 UNIT II: GRADUALLY VARIED FLOW PART- A (2 marks) 1. What are the assumptions made in dynamic equation for gradually varied flow? (N-13) The following assumptions are made for analyzing the gradually varied flow: 1. The flow is steady 2. The pressure distribution over the channel section is hydrostatic, i.e., streamlines are practically straight and parallel. 3. The head loss is same as for uniform flow. 4. The channel slope is small, so that the depth measured vertically is the same as depth measured normal to the channel bottom. 2. Write down the dynamic equation of gradually varied flow. (A-09) Where, S = Slope of the bed Se= Slope of the energy line y =Depth of flow of a rectangular channel V = Velocity of flow 3. What do you mean by gradually varied flow? (N-12) If the change in depth in a varying flow is gradual so that the curvature of the streaming line is not excessive such flow is called gradually varying flow. 4. Mention the methods used for flow profile determination. (N-13) 1. Direct integration method 2. Numerical method 3. Graphical representation method. 5. What are hydraulic curves? Based on depth of water, flow direction and slope of water surface, water surface profile classified into two types: Back water curve and Drawdown curve 6. What are the classifications of channel slopes? Based on channel slopes, channels can be classified into five types as stated earlier. 1. Mild slope (M) 2. Critical slope (C) 3. Steep slope (S) 4. Horizontal slope (H) 5. Adverse slope (A)

7 7. Mention about direct step method. The channel is divided into short reaches and computations are carried out between two ends. Two ends are mentioned as sections1-1 and 2-2. Bernoulli s equation is used to calculate the length of backwater. It is otherwise called step by step method. It is applicable to prismatic channels only. 8. Write about mild slope of water surface flow. (N-12) 1. Flow behind an overflow weir. 2. Flow Over a free overall 3. Flow downstream of a sluice gate. 9. What are the types of numerical method in profile determination? 1. Direct step method 2. Standard step method 12. What is meant by graphical integration method? The differential equation of the gradually varied flow may be inverted and integrated to give the length of the surface profile between depths y1 and y2. Hence the equation for gradually varied flow, dy/dx = S-Se/1-F 2 After integration the above equation becomes, x=l= Above equation is impossible for all types of channel sections, since the equation cannot be expressed explicitly as a function of y. It is integrated graphically by plotting dx/dy against y and computing the area under curve enclose by y-axis and the ordinates of dx/dy corresponding to depths y1 and y How to find the hydraulic mean radius for a rectangular channel? (A-12) Hydraulic mean radius = R = = = 14. Give examples for various types of water surface profiles. 1. M-type surface profiles Eg: M1, M2, M3 2. C-type surface profiles Eg: C1, C3 3.S-type surface profiles Eg: S1, S2, S3 4. H-type surface profiles Eg: H2, H3 5. A-type surface profiles Eg: A2, A3 15. What is the nature of slope of the channel if critical depth line occurs above normal depth line? If the slope of the channel bottom (S) is more than the critical slope (S>Sc), the channel slope is called steep slope.

8 16. Mention about standard step method. (A-09) This method is used for non prismatic or natural channels. In natural channels the cross section varies from section to section and also the cross section information is known only at a few locations along the channel. 17. What is backwater curve in gradually varied flow profile and give practical example for getting this type of profile When the depth of flow (y) increases in the direction of flow, slope of water surface is positive (upward slope) and the water surface is known as Backwater curve. Due to obstruction (dam), the water level raises and it has maximum depth of water near to the dam is an example for back water curve. 18. What is mean by best section? It is known that the conveyance of a channel section increase with increase in the hydraulic radius or with decrease in the wetted perimeter. R = = 9. What do mean by M1 profile? The most common of all gradually varying flow is of M1 type which is a sub critical flow condition obstruction to flow such as weirs, dams etc. which produce M1 profile. 20. Define affux The maximum increase in water level due to obstruction in the path of flow is known as affux. 21. Classify surface profiles in a channel 1. Hydraulic Slope, which is based on the slope of the culvert bottom and 2. Hydraulic Curve, which is based on the relationship of the water depth relative to critical depth and normal depth. 22. Define varied flow. Explain its classification. The depth of flow changes along the length of the channel. Varied flow technically may be either steady or unsteady. Varied flow can be further classified as either rapidly or gradually varied. 23. What are the flow profiles possible in mild sloped channels? M1 profiles are common where mild slope streams enter a pool. M2 profiles can occur upstream of a sudden enlargement in a channel or where the slope becomes steeper. Steep Slope is steeper than critical slope, normal depth is less than critical depth (yn<yc). The flow is supercritical and controlled up stream. 24. Define Subcritical flow. Subcritical occurs when the actual water depth is greater than critical depth. Subcritical flow is dominated by gravitational forces and behaves in a slow or stable way. It is defined as having a Froude number less than one. 25. Define Supercritical flow Supercritical flow is dominated by inertial forces and behaves as rapid or unstable flow. Supercritical flow transitions to subcritical through a hydraulic jump which represents a high energy loss with erosive potential. When the actual depth is less than critical depth it is classified as supercritical. Supercritical flow has a Froude number greater than one.

9 PART- B (16 marks) 1. A river 100m wide and 3m deep has an average bed slope of Estimate the length of the GVF profile produced by a low weir raises the water surface just upstream of it by 1.5 m. Assume n = Use direct step method with three steps. (M-12) 2. What are the assumptions made in the analysis of GVF? Derive the dynamic equation for GVF. 3. With neat diagrams explain the different types of channel slopes. (M-12) 4. What is meant by graphical integration? Explain the various methods of graphical integration in detail. (M-12) 5. A rectangular channel of width 5 m flows 1.5 m in uniform flow bed slope of channel is The uniform flow is blocked by a weir and flow depth of 4 m from bed of the channel. Determine the length of the back water profile between 4 m to 2 m. Use direct step method and assume manning s n as (M-12) 6. Explain the direct step method for computing the length of the water surface profile. 7. Explain the methods of estimating the flow profile. 8. Explain the standard step method to determine the GVF. 9. How surface profiles of GVF are classified and explain them with sketches. (M-12) 10. Derive the relation between sequent depths in open channel.

10 UNIT III: RAPIDLY VARIED FLOW PART - A (2 marks) 1. Write the expression for depth of hydraulic jump? (N-14) Depth of hydraulic jump = y1 y2 Where y1 = depth of flow at section 1-1 y2=depth of flow at section 2-2 F1 = Froude number at section What is the length of hydraulic jump? (N-13) It is defined as the length between section 1-1 and section 2-2 where 1-1 is taken place just before the hydraulic jump and section 2-2 is taken place immediately after the jump. L = 5 to 7 (y2 y1) 3. Distinguish between positive and negative surges. (N-12) Positive surge a surge producing increase in depth Negative surge a surge producing decrease in depth. 4. Define sequent depth. (N-13) These paired depths are known as sequent depths, or conjugate depths. The latter is valid unless the jump is caused by an external force or outside influence 5. What do you mean by length of hydraulic jump? This is defined as the length between the two sections where one section is taken before the hydraulic jump and the second section is taken immediately after the jump. 6. What is the control section of an open channel flow? (A-11) In open channel flow control section is a section where for a given discharge the depth of flow is known or it can be controlled. So the control section for subcritical flow will be at downstream location and the control section for supercritical flow will be at the upstream location. 7. Define hydraulic jump. (N-12) The raise of water level which takes place due to the transformation of the unstable shooting flow (super critical flow) to the stable Streaming flow (sub critical flow) is called hydraulic jump. 8. Mention the critical depth and velocity. (A-11) Depth of flow of water at which the specific energy, E is minimum is called as critical depth (yc). = Velocity of flow at the critical depth is called critical velocity (Vc). Where yc- critical depth g -acceleration due to gravity 9. How to classify the flow as critical, subcritical or super critical? (A-13) Critical flow: Depth of flow of water at which the specific energy is minimum is called as critical flow. Otherwise, flow corresponding to critical depth is called as critical flow. D = area of flow/ top width Sub critical flow:

11 When the depth of flow in a channel is greater than the critical depth yc, the flow is called as sub critical flow. It is otherwise, called as streaming flow or tranquil flow. For sub critical flow, Froude number, F<1 Super critical flow: When the depth of flow in a channel is less than the critical flow, yc, the flow is called as sub critical flow or torrential flow. For supercritical flow, Froude number, F>1 10. What is meant by surges? Surges occurs when there is a sudden change in the discharge/depth and during sudden closure of gate 11. Mention the types of hydraulic jump. (A-12) Based on Froude number (F), hydraulic jump can be classified into 5 types. a. Undulation jump: The Froude number F ranges from 1 to1.7 and the liquid surface does not rise shortly but having undulations of radically decreasing size. b. Weak jump: The Froude number F ranges from1.7 to 2.5 and the liquid surface remains smooth. 12. What do you mean by channel transition? Transition means a change of channel cross section. (i) Provision of a hump or depression along depth and (ii) Contraction or expansion of channel width, in any combination. 14. State about energy dissipation. When hydraulic jump takes place a loss of energy occurs due to eddy formation and turbulence. This loss of energy is equal to the difference of specific energies at sections 1-1 and 2-2. Loss of energy due to hydraulic jump hl = E1-E2 y1 = depth of flow at section 1-1 y2=depth of flow at section Differentiate positive surges from negative surges Positive surge A surge producing on increases in depth. Positive surge moving downstream Negative surge A surge producing on decreases in depth. Negative surge moving upstream 16. What are the conditions for the formation of hydraulic jump? The conditions for the formation of hydraulic jump are: (i)flow is uniform and the pressure distribution is due to hydrostatic before and after the jump. (ii)loss due to friction is small and neglected. (iii)slope of bed channel is small. 17. Mention the uses of hydraulic jump. (A-14) The kinetic energy of flow after the hydraulic jump is greatly reduced, which may prevent erosion of the channel boundaries of downstream side.

12 18. Define transition depth. For rate of flow calculation, instead of reducing width of channel, depth of water is evaluated to certain height is called as hump or transition depth. 19.What is meant by rapidly varying flow? (A-12) If the curvature in a varied flow is large and depth changes appreciably over short length it is called rapidly varying flow20. What is meant by strong jump? When the Froude number greater than 9 and the downstream water surface is rough. Energy loss due to strong jump may be up to 85%. 21. Write down the applications of transition. Transition in open channel flow is made to measure discharge of channel. Generally, discharge, = Area (A) x Velocity (V). For discharge calculation, both cross section of flow and velocity are necessary. With the help of channel transition, discharge of water obtained from measured flow cross section dimensions and / specific energy equations. 22. What is meant by oscillating jump? When the Froude number F ranges from 2.5 to 4.5 and there is an oscillating jet which enters the jump bottom and oscillating to the surface. 1

13 PART - B (16 marks) 1. How surface profiles are classified? Explain the various salient features of profiles. Also write a note on hydraulic jump. (M-13) 2. In a rectangular channel of 0.5m width, a hydraulic jump occurs at a point where depth of water flow is 0.15m and Froude number is 2.5. Determine a) Specific energy b) Critical & subsequent depth c) Loss of head d) Energy dissipated. 3. The depth of flow of water at a certain section of a rectangular channel 2m wide is 0.25m. The discharge through the channel is 1.8m 3 /determines whether a hydraulic jump will occur and determine its height and loss of energy per kg of water. (M-14) 4. A spillway discharges a flood flow at a rate of 7.75m 3 /s per metre width. At the downstream horizontal apron the depth of flow was found to be 0.5m. What tail water depth is needed to form a hydraulic jump? If a jump is formed, find its type, length, head loss, energy loss as percentage of the initial energy. (N-13) 5. Explain with a neat diagram the surges produced when a) A sluice gate is suddenly raised b) A sluice gate is suddenly lowered c) Graphical integration d) Energy dissipation 6. The bed width of a rectangular channel is 2.4m and the depth of flow is 6m. The discharge in the canal is 8.6m 3 /s. The bed slope of the channel is 1 in Assume Chezy s constant C =60. Determine the slope of free water surface. What are the conditions for the formation of hydraulic jump? (N-15) 7. A sluice gate discharges 2.5 m 3 /sec into a wide horizontal rectangular channel. The depth at the vena contracts is 0.2m. The tail water depth is 2.0m, assuming the channel to have a manning s n=0.015, determine the location of the hydraulic jump. 8. During an experiment conducted on a hydraulic jump, in a rectangular open channel 0.5m wide, the depth of water changes from 0.2m to 0.5m. Determine the discharge in the channel and the loss of head due to the formation of hydraulic jump. 9. A horizontal rectangular channel 4m wide carries a discharge of 16 m 3 /sec. Determine whether a jump may occur at an initial depth of 0.5 m or not. If jump occurs determine the sequent depth to this initial depth. 10. State the application of hydraulic jump.

14 UNIT IV: TURBINES PART - A (2 marks) 1. Distinguish between impulse and reaction turbines. (M-12) If at the inlet of the turbine the energy available is only kinetic energy the turbine is known as impulse turbine. If at the inlet of the turbine the water possesses kinetic energy as well as pressure energy the turbine is known as reaction turbine. 2. What is cavitation? How do you prevent cavitations? (M-11) Cavitations is defined as phenomenon of formation of vapor bubbles in a region of a flowing liquid where the pressure in the liquid is falls below than vapor pressure and sudden collapsing of these vapor bubbles in a region of higher pressure. 3. Classify Pelton turbine according to (N-11) (a) The direction of flow through the turbine runner 1. Tangential flow turbine 2. Radial flow turbine 3. Axial flow turbine 4. Mixed flow turbine (b) The action of water on turbine blades. 1. Impulse turbine 2. Reaction turbine 4. Define specific speed of a turbine. It is defined as the speed of a turbine which will develop unit power under unit head. 5. What are the uses of draft tube? 1. The net head on the turbine increases. 2. Due to increase in net head the power and efficiency of the turbine also increases. 3. The large amount of rejected kinetic energy is converted in touseful pressure energy. 6. What are the methods to prevent cavitations? (A-11) The various methods to prevent cavitation are: (i)turbine may be kept under water and keeping low specific speed (ii)cavitation free runner mat be designed (iii)polishing the surface 7. How would you classify turbines based on the direction of flow in the runner? (a) Tangential flow turbine (b) Radial flow turbine (c) Axial flow turbine (d) Mixed flow turbine

15 8. What are the applications of momentum principle? (N-10) The various application of momentum principle are: (i)thrust on a propeller (ii)reaction of a jet (iii)the force exerted by jet of fluid striking on moving (or) fixed plate surface (iv)to determine the resultant force acting on pipe bends 9. Give the classification of turbines. Hydraulic turbines are classified according to several considerations as follows: 1. According to action of water flowing 2. According to the direction of flow of water 3. According to head and quantity of water required 4. According to the specific speed 10. Define draft tube. A tube or pipe of gradually increasing area is used for discharging water from the exit of the turbine to the tail race is called draft tube. 11. Define Specific speed of turbine Specific speed of turbine is defined as turbine which is identical in shape, geometric dimension blade angles, gate opening etc with the actual turbine but of such a size will develop unit power when working under unit head 12. Why is draft tube not used in impulse turbine? (A-13) The draft tube is not used in impulse turbine inorder to increase the working head. 13. Define Overall efficiency of turbine? The overall efficiency of turbine is the ratio of power available at the shaft of the turbine to the power supplied the water at the inlet of turbine. 14. What are the functions of draft tube? (A-12) 1. It allows the turbine to be set above tail-water level without loss of head for doing inspection and maintenance. 2. It regains the major portion of the kinetic energy delivered from the runner by diffuse action. 15. Give examples for reaction turbine. (A-10) Reaction turbine E.g.: Francis turbine, Kaplan turbine, Propeller turbine. 16. Write the classification of turbines based on specific speed. 1. Low specific speed (10 to 35) 2. Medium specific speed (60 to 400) 3. High specific speed (300 to 1000)

16 17. What is radial flow turbine? In a radial flow turbine, water flows along the radial direction and mainly in the plane normal to the axis of rotation, as it passes through the runner. It may be either inward radial flow type or outward radial flow type. 18. What is the overall efficiency in turbines? It is defined as the ratio of power available at the turbine shaft to the power available from the water jet. ηo = Shaft power/ Water power = P/wQH 20. What do you mean by turbine? Turbine is a hydraulic machine which converts the hydraulic energy in to mechanical energy 21.Define - Hydraulic efficiency Hydraulic efficiency is defined as the ratio of power delivered to the runner to the power supplied at the inlet. 22. What are the advantages of draft tubes? (A-09) The pressure at the exit of the runner of a reaction turbine is generally less than the atmosphere pressure. By passing water through the draft tube, the outlet velocity of water is reduced considerably and again in useful pressure head is achieved. Thus the net working head on the turbine increases and therefore the output of the turbine also increases. Draft tube provides a negative suction head at the runner outlet by which it becomes possible to install the turbine above the tailrace level without any loss of head. 23. What is breaking jet? When the nozzle is completely closed, the amount of water striking the runner reduces to zero but the runner due to inertia goes on revolving for a long time to stop the runner in a short time a small nozzle is provided which direct the jet of water on the back of vanes. This jet of water is called breaking jet. 24. What is radial discharge? This means the angle made by absolute velocity with the tangent on the wheel is and the component of whirl velocity is zero 25. Explain Reaction turbine If at the inlet of the turbine the water possesses kinetic energy as well as pressure energy the turbine is known as reaction turbine.

17 PART - B (16 marks) 1. An inward flow reaction turbine supplies water at the rate of 0.60 cumecs at a velocity of flow of 6m/s. The velocity at periphery and velocity of whirl at inlet is 24m/s and 18m/s respectively. Assuming the discharge to be radial at outlet and the velocity of flow constant, determine a) The vane angle at inlet b) The head of water on the wheel (M-14) 2. An inward flow reaction turbine operates under head of 25m running at 200rpm. The peripheral velocity of the runner is 2m/s and the radial velocity at the runner exit is 15m/s. If the hydraulic losses are 20% of the available head, calculate a) The guide vane angle b) The runner vane angle c) The runner diameter d) The specific speed if the width of the runner at the periphery is 30cm e) The power produced by the turbine (M-14) 3. A jet of water diameter strikes a hinged square plate at its centre with a velocity of 20m/s. The plate is deflected through an angle of 20. Find the weight of the plate. If the plate is not allowed to swing, what will be the force required to keep the plate in vertical position. (M-14) 4. A Pelton wheel is to develop 13250KW, a net head of 800m, while running at speed of 600rpm. If the coefficient of jet = 0.97, speed ratio = 0.46 and ratio of jet diameter is 1/15 of wheel diameter. Calculate a) Number of jet b) Diameter of jets c) Diameter of pitch circle d) Quantity of water supplied to wheel. Assume overall efficiency as 85%. 5. The external and internal diameters of an inward flow reaction turbine are 1.2m and 0.6m respectively. The head on the turbine is 22m and the velocity of flow through the runner is constant and equal to 2.5m/s. The guide blade angle is 10 and the runner vanes are radial at inlet. The discharge is radial at outlet. Determine a) The speed of the turbine b) The vane angle at outlet c) Hydraulic efficiency (M-14) 6. Explain the classification of turbines. 7. A Pelton wheel operates with a jet of 150mm diameter under the head of 500m. It means runner diameter is 2.25m and it rates with a speed of 375rpm. The angle of bucket tip at outlet is 15, coefficient of velocity is 0.98, mechanical losses equal to 3% of power supplied and the reduction in relative velocity of water while passing through bucket is 15%. Find the a) Force of jet on the bucket b) Power developed c) Bucket efficiency d) Overall efficiency. (M-14) 8. A Francis turbine is to be designed to develop 360KW under a head of 70m and a speed of 750 rpm. The ratio of width of runner to diameter of runner n is 0.1. The inner diameter of the runner is half of the outer diameter. The flow ratio is The hydraulic efficiency is 95% and the mechanical efficiency is 84%. The percentage of the circumferential area of runner to be occupied by the thickness of the vanes is 4%. The velocity of flow is constant and the discharge is radial at exit. Determine a) Diameter of wheel

18 b) Quantity of water supplied c) Guide vane angle at inlet d) Runner vane angles at inlet and exit 9. A Kaplan turbine runner is to be designed to develop 9100KW. The net available head is 5.6m. If the speed ratio = 2.09, flow ratio = 0.68, overall efficiency 86% and the diameter of the bass is 1/3 the diameter of the runner. Find the diameter of the runner, its speed and the specific speed of the turbine. 10. Classify the turbines based on a) Action of water on turbine blades b) Head on turbines c) Direction of flow through turbine runner d) Specific speed e) Disposition of turbine blade

19 UNIT V: PUMPS PART - A (2 marks) 1. Define Priming. The delivery valve is closed and the suction pipe, casing and portion of the delivery pipe up to delivery valve are completely filled with the liquid so that no air pocket is left. This is called as priming. 2. What is the significance of air vessel? (M-14) To obtain a continuous supply of liquid at a uniform rate. To run the pump at a high speed without separation. 3. Why is the theoretical suction height of a pump limited? Theoretically a pump will raise water a distance equal to the height that atmospheric pressure is 10.3m. 4. Define negative slip. How it occurs? (M-15) Slip is defined as the difference between theoretical discharge and actual discharge. If actual discharge is greater than theoretical discharge negative value is found, this negative value is called negative slip. 5. What is separation of reciprocating pump? If the pressure in the cylinder is below the vapour pressure, dissolved gasses will be liberated from the liquid andcavitations will takes place. The continuous flow of liquid will not ex it which means separation of liquid takes place. The pressure at which separation takes place is called separation pressure and head corresponding to the separation pressure is called separation pressure head. 6. Draw and define an ideal indicator diagram. Indicator diagram is the graph plotted between the pressure head in the cylinder and distance traveled by the piston from inner dead center for one complete revolution of the crank. 7. Define specific speed of a pump. (N-11) It is defined as the speed of a pump which will develop unit quantity under unit head. 8. Why the theoretical suction height of a pump is limited? (N-14) The theoretical suction height of a pump is limited inorder to avoid cavitation, the negative pressure at the inlet to the pump is kept within permissible limits. 9. Define Specific speed of a pump The specific speed of a pump is defined as the speed of a geometrically similar pump which would deliver one cubic metre of liquid per second against a head of one metre. 10. Draw and define an ideal indicator diagram. Indicator diagram is the graph plotted between the pressure head in the cylinder and distance traveled by the piston from inner dead center for one complete revolution of the crank. 11. Define specific speed of a pump. It is defined as the speed of a pump which will develop unit quantity under unit head. 12. Why the theoretical suction height of a pump is limited? The theoretical suction height of a pump is limited inorder to avoid cavitation, the negative pressure at the inlet to the pump is kept within permissible limits.

20 13. Define Specific speed of a pump The specific speed of a pump is defined as the speed of a geometrically similar pump which would deliver one cubic metre of liquid per second against a head of one metre. 13. How to find the hydraulic mean radius for a rectangular channel? (A-12) Hydraulic mean radius = R = = = 14. Give examples for various types of water surface profiles. 1. M-type surface profiles Eg: M1, M2, M3 2. C-type surface profiles Eg: C1, C3 3.S-type surface profiles Eg: S1, S2, S3 4. H-type surface profiles Eg: H2, H3 5. A-type surface profiles Eg: A2, A3 15. What is the nature of slope of the channel if critical depth line occurs above normal depth line? If the slope of the channel bottom (S) is more than the critical slope (S>Sc), the channel slope is called steep slope. 16. Mention about standard step method. (A-09) This method is used for non prismatic or natural channels. In natural channels the cross section varies from section to section and also the cross section information is known only at a few locations along the channel. 17. What is backwater curve in gradually varied flow profile and give practical example for getting this type of profile When the depth of flow (y) increases in the direction of flow, slope of water surface is positive (upward slope) and the water surface is known as Backwater curve. Due to obstruction (dam), the water level raises and it has maximum depth of water near to the dam is an example for back water curve. 18. What is mean by best section? It is known that the conveyance of a channel section increase with increase in the hydraulic radius or with decrease in the wetted perimeter. R = = 19. What do mean by M1 profile? The most common of all gradually varying flow is of M1 type which is a sub critical flow condition obstruction to flow such as weirs, dams etc. which produce M1 profile. 20.Define affux The maximum increase in water level due to obstruction in the path of flow is known as affux. 21. Classify surface profiles in a channel 1. Hydraulic Slope, which is based on the slope of the culvert bottom and 2. Hydraulic Curve, which is based on the relationship of the water depth relative to critical depth and normal depth.

21 22. Define varied flow. Explain its classification. The depth of flow changes along the length of the channel. Varied flow technically may be either steady or unsteady. Varied flow can be further classified as either rapidly or gradually varied.

22 PART - B (16 marks) 1. A single acting reciprocating pump having a cylinder diameter of 150mm and stroke of 300mm is used to raise the water through a height of 20m. Its crank rotates at 60rpm. Find the theoretical power required to run the pump and the theoretical discharge. If actual discharge of 5 l/s, find the percentage slip. If the delivery pipe is 100mm in diameter and is 15m long, find the acceleration head at the beginning of stroke. (M-10) 2. The impeller of a centrifugal pump having external and internal diameter 500mm and 250mm respectively, width at outlet 50mm and running at 1200rpm, working against a head of 48m. The velocity of flow through the impeller is constant and equal to 3m/s. The vanes are set back at an angle of 45 at outlet. Determine a) Inlet vane angle b) Work done by the impeller c) Manometric efficiency 3. A single acting reciprocating pump having plunger diameter 125mm and stroke length 300mm is drawing water from a depth of 4m from the axis of the cylinder at 24rpm. The length and diameter of suction pipe is 9m and 75mm respectively. Determine the pressure head on the piston at the beginning, middle and the suction pipe. (M-10) 4. Draw the indicator diagram of a reciprocating pump for the following cases: a) Without air vessels on both suction & delivery sides b) With air vessels only on suction side 5. A three throw pump has cylinders of 250mm diameter and stroke of 500mm each. The pump is required to deliver 0.1m 3 /sec at a head of 100m. Friction losses are estimated to be 1m in the suction pipe and 19m in delivery pipe. Velocity of water in delivery pipe is 1m/s, overall efficiency is 85% and slip is 3%. Determine a) Speed of the pump b) Power required for running the pump (M-10) 6. Explain with a neat sketch, the construction and working principle of reciprocating pump 7. Explain the following with the neat sketch. a) Centrifugal pump b) Jet pump 8. The three stage centrifugal pump has impellers 500mm in diameter and 60mm width at outlet. All the impellers are keyed to the same shaft. The vanes of each impeller are having outlet angle as 40.The speed of the pump is 400rpm and the total manometric head developed is 25m. If the discharge through the pump is 0.12m 3 /s. Find the manometric efficiency. 9. Write short notes on the following: a) Manometric efficiency b) Volumetric efficiency c) Mechanical efficiency d) Overall efficiency of the centrifugal pump 10. A centrifugal pump is to discharge 0.118m 3 /s at a speed of 1450rpm against a head of 25m. The impeller diameter is 250mm, its width at outlet is 50mm and manometric efficiency is 75%. Determine the vane angle at the outer periphery of the impeller.