SHRI RAMSWAROOP MEMORIAL COLLEGE OF ENGG. & MANAGEMENT

Size: px

Start display at page:

Download "SHRI RAMSWAROOP MEMORIAL COLLEGE OF ENGG. & MANAGEMENT"

Sybil Franklin
6 years ago
Views:

1 SHRI RAMSWAROOP MEMORIAL COLLEGE OF ENGG. & MANAGEMENT B.Tech. [SEM IV (ME-41,42,43,44,45 & 46)] QUIZ TEST-2 (Session: ) APPLIED THERMODYNAMICS (EME-401) Q.1) In a gas turbine installation air is supplied at 1 bar, 27 0 C into compression ratio of 8. The air leaving combustion chamber is heated upto 1100 K and expanded upto 1 bar. A heat exchanger having effectiveness of 0.8 is fitted at exit of turbine for heating the air before its inlet into combustion chamber. Assuming polytrophic efficiency of the compressor and turbine as 0.85 and 0.90 determine cycle efficiency, work ratio and specific work output of plant. Take c p = kj/kg. K for air. Q.4 [2+2+1] Q.2) Explain the working of a turbo-jet engine with the help of a T-S diagram. Q.10 [5] Q.1) In a gas turbine cycle, air at 27 C and 0.98 bar is compressed to 6 bar. The temperature of air is increased to 750 C as it passes through the combustion chamber. The isentropic efficiencies of compressor and turbine are 0.8 and 0.85 respectively. Determine the efficiency of the plant. [6] Q.2) In a constant pressure open cycle gas turbine, air enters at 1 bar and 20 C and leaves the compressor at 5 bar. Using the following data: Temperature of gases entering the turbine is 680 C. Pressure loss in combustion chamber is 0.1 bar compressor =85%, turbine =80%, compressor =85%, γ=1.4 and C p =1.024 kj/kgk for air and gas, find: (i) The quantity of air circulation if the plant develops 1000kW. (ii) Heat supplied per Kg of air circulation. (iii) Thermal efficiency of the cycle. [3+3+3] Q.3) Compare a gas turbine with internal combustion engine and steam turbine. [5] EME-401/Mr C.B. Khatri Date:06/04/2013 Page-1

2 B SHRI RAMSWAROOP MEMORIAL COLLEGE OF ENGG. & MANAGEMENT B.Tech. [SEM IV (ME-41,42,43,44,45 & 46)] QUIZ TEST-2 (Session: ) APPLIED THERMODYNAMICS (EME-401) Q.1) In an air standard Brayton cycle the minimum and maximum temperature are 300 K and 1200 K, respectively. The pressure ratio is that which maximizes the net work developed by the cycle per unit mass of air flow. Calculate the compressor and turbine work, each in kj/kg air, and thermal efficiency of the cycle. Q.1 [2+2+1] Q.2) A turbo jet engine consumes air at the rate of 60 kg/s when flying at a speed of 1000 kmph. Calculate the (i) Exit velocity of the jet when the enthalpy change in the nozzle is 245 kj/kg, nozzle efficiency =0.9, velocity coefficient =0.98. (ii) Thrust and specific fuel consumption if the air fuel ratio is 70. Q.8 [3+2] Q.1) In a gas turbine cycle, air at 27 C and 0.98 bar is compressed to 6 bar. The temperature of air is increased to 750 C as it passes through the combustion chamber. The isentropic efficiencies of compressor and turbine are 0.8 and 0.85 respectively. Determine the efficiency of the plant. [6] Q.2) In a constant pressure open cycle gas turbine, air enters at 1 bar and 20 C and leaves the compressor at 5 bar. Using the following data: Temperature of gases entering the turbine is 680 C. Pressure loss in combustion chamber is 0.1 bar compressor =85%, turbine =80%, compressor =85%, γ=1.4 and C p =1.024 kj/kgk for air and gas, find: (i) The quantity of air circulation if the plant develops 1000kW. (ii) Heat supplied per Kg of air circulation. (iii) Thermal efficiency of the cycle. [3+3+3] Q.3) Compare a gas turbine with internal combustion engine and steam turbine. EME-401/Mr C.B. Khatri Date:06/04/2013 [5] Page-2

3 C SHRI RAMSWAROOP MEMORIAL COLLEGE OF ENGG. & MANAGEMENT B.Tech. [SEM IV (ME-41,42,43,44,45 & 46)] QUIZ TEST-2 (Session: ) APPLIED THERMODYNAMICS (EME-401) Q.1) A gas turbine plant has air being supplied at 1 bar, 27 0 C to compressor for getting compressed upto 5 bar with isentropic efficiency of 85%. Compressed air is heated upto 1000 K in combustion chamber where also occurs a pressure drop of 0.2 bar. Subsequently expansion occurs to 1 bar in turbine. Determine isentropic efficiency of turbine, if thermal efficiency of plant is 20%. Neglect the air property variation throughout cycle. Take γ = 1.4 Q.2) Draw a schematic diagram of ram jet engine. Explain its working, merits and demerits. Q.5 [3+2] Q.11 [5] Q.1) In a gas turbine cycle, air at 27 C and 0.98 bar is compressed to 6 bar. The temperature of air is increased to 750 C as it passes through the combustion chamber. The isentropic efficiencies of compressor and turbine are 0.8 and 0.85 respectively. Determine the efficiency of the plant. [6] Q.2) In a constant pressure open cycle gas turbine, air enters at 1 bar and 20 C and leaves the compressor at 5 bar. Using the following data: Temperature of gases entering the turbine is 680 C. Pressure loss in combustion chamber is 0.1 bar compressor =85%, turbine =80%, compressor =85%, γ=1.4 and C p =1.024 kj/kgk for air and gas, find: (i) The quantity of air circulation if the plant develops 1000kW. (ii) Heat supplied per Kg of air circulation. (iii) Thermal efficiency of the cycle. [3+3+3] Q.3) Compare a gas turbine with internal combustion engine and steam turbine. EME-401/Mr C.B. Khatri Date:06/04/2013 [5] Page-3

4 D SHRI RAMSWAROOP MEMORIAL COLLEGE OF ENGG. & MANAGEMENT B.Tech. [SEM IV (ME-41,42,43,44,45 & 46)] QUIZ TEST-2 (Session: ) APPLIED THERMODYNAMICS (EME-401) Q.1) A gas turbine plant receives at a pressure of 1 bar and 290K. The air is compressed in a rotary compressor to a pressure of 4bar and then heated to a temperature of 840K. The efficiencies of compressor and turbine are 82% and 86% respectively. Neglecting the pressure drop, find overall efficiency of the plant (i) without heat exchanger; and (ii) with heat exchanger of 70% effectiveness. Take γ and Cp for air and hot gases as 1.4 and 1 kj/kgk respectively. Q.6 [3+2] Q.2) What are the advantages of a rocket engine? Also discuss its demerits. Q.12 [5] Q.1) In a gas turbine cycle, air at 27 C and 0.98 bar is compressed to 6 bar. The temperature of air is increased to 750 C as it passes through the combustion chamber. The isentropic efficiencies of compressor and turbine are 0.8 and 0.85 respectively. Determine the efficiency of the plant. [6] Q.2) In a constant pressure open cycle gas turbine, air enters at 1 bar and 20 C and leaves the compressor at 5 bar. Using the following data: Temperature of gases entering the turbine is 680 C. Pressure loss in combustion chamber is 0.1 bar compressor =85%, turbine =80%, compressor =85%, γ=1.4 and C p =1.024 kj/kgk for air and gas, find: (i) The quantity of air circulation if the plant develops 1000kW. (ii) Heat supplied per Kg of air circulation. (iii) Thermal efficiency of the cycle. [3+3+3] Q.3) Compare a gas turbine with internal combustion engine and steam turbine. EME-401/Mr C.B. Khatri Date:06/04/2013 [5] Page-4

5 E SHRI RAMSWAROOP MEMORIAL COLLEGE OF ENGG. & MANAGEMENT B.Tech. [SEM IV (ME-41,42,43,44,45 & 46)] QUIZ TEST-2 (Session: ) APPLIED THERMODYNAMICS (EME-401) Q.1) A gas turbine unit receives air at 1 bar, 300 K and compresses it adiabatically to 6.2 bar. The compressor efficiency is 88%. The turbine internal efficiency is 90%. Calculate the work of turbine and compressor per kg of air. For products of combustion c p = 1.147kJ/kg, γ = Q.2 [3+2] Q.2) An aircraft is flying at an altitude of 10 km (ρ a =0.17 kg/m 3 ) at a speed of 900km/h. The propulsive efficiency is 60%, overall efficiency is 20%, and drag on the aircraft is 6.5 kn. If the heating value of the fuel is 45 MJ/kg, calculate the Jet velocity at exit. Q.9 [5] Q.1) In a gas turbine cycle, air at 27 C and 0.98 bar is compressed to 6 bar. The temperature of air is increased to 750 C as it passes through the combustion chamber. The isentropic efficiencies of compressor and turbine are 0.8 and 0.85 respectively. Determine the efficiency of the plant. [6] Q.2) In a constant pressure open cycle gas turbine, air enters at 1 bar and 20 C and leaves the compressor at 5 bar. Using the following data: Temperature of gases entering the turbine is 680 C. Pressure loss in combustion chamber is 0.1 bar compressor =85%, turbine =80%, compressor =85%, γ=1.4 and C p =1.024 kj/kgk for air and gas, find: (i) The quantity of air circulation if the plant develops 1000kW. (ii) Heat supplied per Kg of air circulation. (iii) Thermal efficiency of the cycle. [3+3+3] Q.3) Compare a gas turbine with internal combustion engine and steam turbine. [5] EME-401/Mr C.B. Khatri Date:06/04/2013 Page-5

6 EME-401/Mr C.B. Khatri Date:06/04/2013 Page-6

7 SHRI RAMSWAROOP MEMORIAL COLLEGE OF ENGG. & MANAGEMENT B.Tech. [SEM IV (ME)] QUIZ TEST-1 (Session: ) APPLIED THERMODYNAMICS (EME-401) Q.1) What do you understand by Gibbs function? How does it differ from the availability function? Q.1 [5] Q.2) During production of gas the air and steam are passed through an incandescent coal bed. The coal is seen to have 95% of carbon and remaining as incombustible. The gas produced has hydrogen, nitrogen and carbon monoxide. Determine, the steam required per kg of coal and total air required per kg of coal when the heat of formation for steam is kj/kg of hydrogen and for carbon monoxide it is kj/kg of carbon. Also obtain volumetric analysis of gas. Take temperature of water as 20 0 C at 1atm pressure. Take air to have 23.2% O 2 and 76.8% N 2 by mass. Q.8 [3+2] Q.1) Derive the following relation or specific heats: C p C v = - T [5] Q.2) The products of combustion of an unknown hydrocarbon C x H y have the following composition as measured by orsat apparatus CO 2 =8%, CO=0.9%,O 2 =8.8% and N 2 =82.3%. Determine: (a) Composition of the fuel (b) Air Fuel Ratio (c) Percentage of excess air used. [3+3+3] Q.3) Write short notes on the following: (a) Heating value of fuel. (b) Adiabatic Flame temperature. [3+3] EME-302 /Mr C.B.Khatri, Ms. Preeti Tiwari Date: 11/02/2013 Page-1

8 SHRI RAMSWAROOP MEMORIAL COLLEGE OF ENGG. & MA B.Tech. [SEM III (CE)] QUIZ TEST-1 (Session : ) STRENGTH OF MATERIAL (EME-302) Q.1 A block of material is subjected to a tensile strain of and a compressive strain of on a planes at r shear strain of and there is no strain on a planes at right angles to above planes. Calculate the principal strain Q.9 [2+3] Q.2.. At a point in a material under stress, the intensity of the resultant stress on a certain plane is 50MN/m 2 (tensile) inclined at 30 0 to normal of that plane. The stress on a plane at right angles to this has a normal ten Find (i) Resultant stress on the second plane. (ii) The principal plane and stresses (iii)the plane of maximum shear and its intensity. Q.6[1+2+2] Q.1. There is a stressed point as shown in fig.(a), find out the following (i) Normal and tangential stress on the oblique section. [1+1] (ii) Principal stresses, maximum shear stresses and their planes. [ ] (iii) Verify it with the use of Mohr circle.(scaling is not necessary) [2] Q.2. At a point A in a body, σ xx = 80kN/ cm 2,σ yy = -20kN/cm 2,σ zz = 20kN/cm 2 and τ xy =τ yz = τ zx = 20kN/cm 2, determine normal and shearing stresses on a plane which is parallel to the X+Y+Z=1. [3+3] Q.3. Design a steel bolt subjected to compressive load 30 kn along with a shear force of 15 kn. The yield point for the material is 300 Mpa and µ(poison ratio) = 0.3. Calculate the safe diameter by, Maximum shear stress theory and Maximum total strain energy theory. Take FOS= 2.5. [2+4] EME-302 /Mr C.B.Khatri, Ms. Preeti Tiwari Date: EME /02/2013 /Mr C.B.Khatri,Krishna kr. Yadav and Harsh Dwivedi Date: 08/09/2012 Page-2

9 SHRI RAMSWAROOP MEMORIAL COLLEGE OF ENGG. & MANAGEMENT B.Tech. [SEM III (CE)] QUIZ TEST-1 (Session : ) STRENGTH OF MATERIAL (EME-302) Q.1. Two mutually perpendicular planes of an element of material are subjected to direct stresses of 10.5 MN/m 2 (tensile) and 3.5 MN/m 2 (compressive) and shear stress of 7 MN/m 2. Find graphically or otherwise: (i) magnitude and direction of principal stress, and (ii) The magnitude of the normal and shear stresses on a plane on which the shear stress is maximum. Q.5 [2+3] Q.2. Estimate the principal stresses acting on the plate which gave the following results: Principal strain, e 1 = ; e 2 = Modulus of elasticity, E= 200GN/m 2, Poisson s ratio, 1/m = 0.2 Q.7 [2+3] Q.1. There is a stressed point as shown in fig.(a), find out the following (i) Normal and tangential stress on the oblique section. [1+1] (ii) Principal stresses, maximum shear stresses and their planes. [ ] (iii) Verify it with the use of Mohr circle.(scaling is not necessary) [2] Q.2. At a point A in a body, σ xx = 80kN/ cm 2,σ yy = -20kN/cm 2,σ zz = 20kN/cm 2 and τ xy =τ yz = τ zx = 20kN/cm 2, determine normal and shearing stresses on a plane which is parallel to the X+Y+Z=1. [3+3] Q.3. Design a steel bolt subjected to compressive load 30 kn along with a shear force of 15 kn. The yield point for the material is 300 Mpa and µ(poison ratio) = 0.3. Calculate the safe diameter by, Maximum shear stress theory and Maximum total strain energy theory. Take FOS= 2.5. [2+4] Page-3 EME-302 /Mr C.B.Khatri, Ms. Preeti Tiwari Date: 11/02/2013

10 SHRI RAMSWAROOP MEMORIAL COLLEGE OF ENGG. & MANAGEMENT B.Tech. [SEM III (CE)] QUIZ TEST-1 (Session : ) STRENGTH OF MATERIAL (EME-302) Q.1. Direct stresses of 120MN/m 2 in tension and 90MN/m 2 in compression are applied to an elastic material at a certain point on planes at a right angle to another. If the maximum principal stress is not exceeding 150 MN/m 2 in tension, to what shearing stress can material be subjected? What is the maximum resulting shearing stress in the material? Also find the magnitude of the other principal stress. Q.4 [2+3] Q.2 A steel shaft is subjected to an end thrust producing a stress of 90 MPa and minimum shearing stress on the surface arising from torsion is 60 MPa. The yield point of the material in simple tension was found to be 300 MPa. Calculate the FOS of the shaft according to the maximum distortion energy theory. Q.13 [2+3] Q.1. There is a stressed point as shown in fig.(a), find out the following (i) Normal and tangential stress on the oblique section. [1+1] (ii) Principal stresses, maximum shear stresses and their planes. [ ] (iii) Verify it with the use of Mohr circle.(scaling is not necessary) [2] Q.2. At a point A in a body, σ xx = 80kN/ cm 2,σ yy = -20kN/cm 2,σ zz = 20kN/cm 2 and τ xy =τ yz = τ zx = 20kN/cm 2, determine normal and shearing stresses on a plane which is parallel to the X+Y+Z=1. [3+3] Q.3. Design a steel bolt subjected to compressive load 30 kn along with a shear force of 15 kn. The yield point for the material is 300 Mpa and µ(poison ratio) = 0.3. Calculate the safe diameter by, Maximum shear stress theory and Maximum total strain energy theory. Take FOS= 2.5. [2+4] EME-302 /Mr C.B.Khatri, Ms. Preeti Tiwari Date: 11/02/2013 Page-4

11 SHRI RAMSWAROOP MEMORIAL COLLEGE OF ENGG. & MANAGEMENT B.Tech. [SEM III (CE)] QUIZ TEST-1 (Session : ) STRENGTH OF MATERIAL (EME-302) Q.1. Draw the Mohr s stresses circle for direct stresses of 65 MN/m 2 and 35 MN/m 2 (compressive) and estimate the magnitude and direction of the resultant stresses on planes making angle of 20 0 and 65 0 with the plane of the first principal stress. Find also the normal and tangential stresses on these planes Q.3 [2+3] Q.8.. A mild steel shaft 120 mm diameter is subjected to a maximum torque of 20 KNm and maximum bending moment of 12 KNm at a particular section. Find the FOS according to the maximum shear stress theory if the elastic limit in simple tension is 220 MN/m 2. Q.12 [2+3] Q.1. There is a stressed point as shown in fig.(a), find out the following (i) Normal and tangential stress on the oblique section. [1+1] (ii) Principal stresses, maximum shear stresses and their planes. [ ] (iii) Verify it with the use of Mohr circle.(scaling is not necessary) [2] Q.2. At a point A in a body, σ xx = 80kN/ cm 2,σ yy = -20kN/cm 2,σ zz = 20kN/cm 2 and τ xy =τ yz = τ zx = 20kN/cm 2, determine normal and shearing stresses on a plane which is parallel to the X+Y+Z=1. [3+3] Q.3. Design a steel bolt subjected to compressive load 30 kn along with a shear force of 15 kn. The yield point for the material is 300 Mpa and µ(poison ratio) = 0.3. Calculate the safe diameter by, Maximum shear stress theory and Maximum total strain energy theory. Take FOS= 2.5. [2+4] EME-302 /Mr C.B.Khatri, Ms. Preeti Tiwari Date: 11/02/2013 Page-5

12 EME-302 /Mr C.B.Khatri, Ms. Preeti Tiwari Date: 11/02/2013 Page-6

Code No: RR Set No. 1

Code No: RR Set No. 1 Code No: RR310303 Set No. 1 III B.Tech I Semester Regular Examinations, November 2006 THERMAL ENGINEERING-II (Mechanical Engineering) Time: 3 hours Max Marks: 80 Answer any FIVE Questions All Questions