HEAT TRANSFER ANALYSIS OF AL 2 O 3 NANOFLUID IN CIRCULAR TUBE WITH COPPER PLATE WINDING

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1 International Journal of Emerging Technology and Innovative Engineering Volume 3, Issue 1, January 217 (ISSN: ) HEAT TRANSFER ANALYSIS OF AL 2 O 3 NANOFLUID IN CIRCULAR TUBE WITH COPPER PLATE WINDING A. VembathuRajesh 1*, V.Sivaganesan 2, B.Nagarajan 3, P.Surulimani 4, A.Karthik Raja 5 1, 2, 3, 4 & 5 Assistant Professors, Department of Mechanical Engineering, Nadar Saraswathi College of Engineering and Technology, Theni, Tamil Nadu, India. *Corresponding Author ID: avr.krj@gmail.com ABSTRACT Heat transfer analysis of Al 2 O 3 nanofluid in a copper tube with copper plate winding is experimentally investigated. Experiments are conducted with water and nanofluid of.1 % particle volume for different temperatures 35 C, 4 C, 45 C and 5 C. with various volume flow rate under forced convection. It is seen that the heat transfer rate increases with volume flow rate. The Reynolds Number increases with volume flow rate and is high for water +.1 % Al 2 O 3 nanofluid than water for the same temperature. But the Nusselt Number decreases with increase in volume flow rate and is low for water +.1 % Al 2 O 3 nanofluid than water. However from the figures it can be seen that the value of heat transfer rate of water +.1% Al 2 O 3 nanofluid is high for all temperatures and various volume flow rates as compared to heat transfer rate value of water for the same correlations. So it can be concluded that with increase in temperature with various volume flow rate, the heat transfer coefficient of water +.1% Al 2 O 3 nanofluid increases than water. The experimental results show that the winding of copper tube with copper plate has considerable effect on the heat transfer characteristics of Al 2 O 3 nanofluid than water. Keywords: Al 2 O 3 nanofluid, Copper plate winding, Circular tube, Heat transfer analysis 1. INTRODUCTION Nanofluid is a fluid containing nanometer-sized particles, called nanoparticles. These fluids are engineered colloidal suspensions of nanoparticles in a base fluid. The nanoparticles used in nanofluids are typically made of metals, oxides, carbides, or carbon nanotubes. Common base fluids include water, ethylene glycol and oil. Nanofluids have novel properties that make them potentially useful in many applications in heat transfer, including microelectronics, fuel cells, pharmaceutical processes, and hybrid - powered engines, engine cooling / vehicle thermal management, domestic refrigerator, chiller, heat exchanger, nuclear reactor coolant, in grinding, machining, in space technology, defense and ships, and in boiler flue gas temperature reduction. They exhibit enhanced thermal conductivity and the convective heat transfer coefficient compared to the base fluid. Knowledge of the rheological behavior of nanofluids is found to be very critical in deciding their suitability for convective heat transfer applications. A lot of work has been done recently on the forced convective heat transfer of nanofluids in pipe flow. H. Almohammadi et.al. [1] investigated experimentally the convective heat transfer coefficient and pressure drop of Al 2 O 3 /water nanofluid in laminar flow regime under constant heat flux conditions inside a circular tube. They reported that the average heat transfer coefficient enhanced about 11-2% with.5% volume concentration and increased about 16-27% with 1% volume concentration compared to distilled water. They observed that the convective heat transfer coefficient of nanofluid enhances with increase in heat flux and there is no significant increase in friction factor for nanofluids. Abdulhassan Abd. K et.al. [2] measured the pressure drop and convective heat transfer coefficient of water based AL (25nm), Al 2 O 3 (3nm) and CuO (5nm) Nanofluids flowing through a uniform heated circular tube in the fully developed laminar flow regime. They demonstrated that the amount of the increase in heat transfer coefficient for three types of Nanofluid was AL, Al 2 O 3, and CuO and these ratios were respectively (45%, 32%, 25%) with insulation and without insulation (36%, 23%, 19%), and the statement of any of the cases the best increase in heat transfer has been proven that using insulation is better than not using it. L. Syam Sundar et.al. [3] investigated the fully developed laminar convective heat transfer and friction factor characteristics of 448

2 different volume concentrations of Al 2 O 3 nanofluid in a plain tube and fitted with different twist ratios of twisted tape inserts. The nanofluid heat transfer coefficient was high compared to water and further heat transfer enhancement was observed with twisted tape inserts. The pressure drop increased slightly with the inserts, but is comparatively negligible. They developed a generalized regression equation based on the experimental data for the estimation of the Nusselt number and friction factor for water and nanofluid in a plain tube and with twisted tape inserts. Heris et al. [4] investigated experimentally the laminar flow forced convection heat transfer of Al 2 O 3 /water nanofluid inside a circular tube with constant wall temperature. They obtained the Nusselt numbers of nanofluids for different nanoparticle concentrations as well as various Peclet and Reynolds numbers. Experimental results emphasized the enhancement of heat transfer due to the nanoparticles presence in the fluid. They observed that the heat transfer coefficient increased by increasing the concentration of nanoparticles in nanofluid. Kyo Sik Hwang et.al. [5] measured the pressure drop and convective heat transfer coefficient of water-based Al 2 O 3 nanofluids flowing through a uniformly heated circular tube in the fully developed laminar flow regime. They found that the data for nanofluid friction factor show a good agreement with analytical predictions from the Darcy s equation for single-phase flow. However, the convective heat transfer coefficient of the nanofluids increased by up to 8% at a concentration of.3 vol % compared with that of pure water and this enhancement cannot be predicted by the Shah equation. M. A. K. Chowdhuri et.al. [6] carried out the experiment to study the turbulent flow heat transfer and to determine the pressure drop characteristics of air, flowing through a tube with insert. They used an insert of special geometry inside the tube. They found that heat transfer through tube can be enhanced by using inserts inside the tube up to 9.8 times than tube without insert. S. Suresh et.al. [7] carried out an experimental investigation on the convective heat transfer and friction factor characteristics in the plain and dimpled tube under laminar flow with constant heat flux with distilled water and CuO/water nanofluids. They used CuO nanoparticles with an average size of 15.3 nm were synthesized by sol gel method. They found that the experimental Nusselt numbers for.1,.2 and.3% volume concentration of CuO nanoparticles were about 6, 9.9 and 12.6%, respectively higher than those obtained with distilled water in plain tube. However, the experimental Nusselt numbers for.1,.2 and.3% volume concentration of CuO nanoparticles were about 3.4, 6.8 and 12%, respectively higher than those obtained with distilled water in dimpled tube. They also found that the friction factor of CuO/water nanofluid was also increased due to the inclusion of nanoparticles and found to increase with nanoparticle volume concentration. P.K.Nagarajan et.al. [8] investigated experimentally the heat transfer and friction factor characteristics of circular tube fitted with 3 right-left helical screw inserts with 1 mm spacer of different twist ratio for laminar and turbulent flow. They compared the experimental data with those obtained from plain tube published data. The heat transfer coefficient enhancement for 3 RL inserts with 1 mm spacer was quite comparable with for 3 R-L inserts. They found that the type of twist inserts can be used effectively for heat transfer augmentation. Kumbhar D.G et.al. [9] reviewed the research work in last decade on heat transfer enhancement in a circular tube. They focused on dealing with twisted tape inserts and found that the thermo hydraulic performance of twisted tape insert depends on the flow conditions i.e., laminar or turbulent flow apart from the insert configuration. Saad A. El-Sayed et.al. [1] have performed an experimental investigation to determine the detailed module-by-module pressure drop and heat transfer coefficient of turbulent flow inside a circular finned tube. They used tubes provided with longitudinal fins continuous or interrupted in the stream wise direction by arranging them both in a staggered and inline manner. They carried out experiments for two different fin geometries, with two numbers of fins (N = 6 and 12). The module-by-module heat transfer coefficient is found to vary only in the first modules, and then attained a constant thermally periodic fully developed value after eight to twelve modules. The results also showed that in the periodic hydrodynamic fully developed region, the value of the pressure drop along the tube with continuous fins is greater than that of the in-line arrangement, and lower than that of the staggered arrangement. Furthermore, the results showed that in the periodic fully developed region, the tube with continuous fins produces a greater value of the heat transfer coefficients than that the tube with interrupted fins, especially through a high range of Reynolds number (5 14 > Re > 2 14). The tube with Staggered arrangement of fins produces a greater value of the heat transfer coefficient than the tube with continuous fins and the in-line arrangement finned tube at low Reynolds number (Re < ).). It was found that the fins efficiency is greater than 9 percent; in the worst case (maximum Reynolds number with 449

3 continuous fins tube). Anoop et al. [11] investigated on the convective heat transfer characteristics in the developing region of tube flow with constant heat flux with alumina water nanofluids experimentally. They used two particle sizes, one with average particle size off 45 nm and the other with 15 nm. They observed that both nanofluids showed higher heat transfer characteristics than the base fluid and the nanofluid with 45 nm particles showed higher heat transfer coefficient than that with 15 nm particles and also in the developing region, the heat transfer coefficients show higher enhancement than in the developed region. Based on the experimental results they proposed a correlation for heat transfer in the developing region for the present range of nanofluids. by the pump from the reservoir to flow through the test loop. A ten liter capacity stainless steel vessel equipped by drain valve is used as fluid reservoir. The copper tube of six passes shaped as u tube is provided with five K-type thermocouples, brazed to the surface at each tube passes and two located to measure the working fluid inlet and outlet temperatures. All these thermocouples have.1 C resolution and are calibrated before fixing them at the specified locations. The fluid is forced through the test section with the aid of a pump, the suction side connected to a storage tank. The storage tank is made of stainless steel of 1 liters capacity. The liquid which is heated in the storage tank is allowed to return back to the storage tank for recirculation. 2. PREPARATION OF NANOFLUIDS Some properties of hydrophilic rod-like Al 2 O 3 nanoparticles (AF-alumina type) and base fluid (water) which have been used for assessing the nanofluid properties are tabulated in Table 1. The AF alumina type nanoparticle is rod-like and because of its cylindrical shape and elongation, it has a better heat conduction through the fluid rather than spherical nanoparticles. However the spherical nanoparticles are often most readily available at the best prices. Table 1 Material Properties Material properties AF alumina Specific heat (J kg 1 K 1) Density (kgm 3) Thermal conductivity (Wm 1 K 1) Size nm 3. EXPERIMENTAL SET UP A tube of six passes shaped as u shape with 1 mm length, 1 mm internal diameter, and 1.5 mm outer diameter was used as the test section. The tube used in the test is made up of copper and is winded by a copper plate. The copper plate is made in the laboratory from a.5 mm thick and 5 m length is wound over the full length of the copper tube. The copper tube wounded with copper plate is as shown in figure. The test loop consists of a storage vessel, pump, temperature controller, temperature indicator panel and a test section. The pump used in this work was of peristaltic type. The pump could deliver a maximum flow rate of 3 liters per minute. Nanofluids were driven Figure 2 Schematic view of experimental setup The fluid flows through a copper tube, collecting tank, a storage tank with the aid of a pump. The working fluid is heated uniformly by a nichrome heater in the storage tank and subject entire test section to constant heat flux boundary condition. After the experimental setup is assembled, the storage tank is filled with the working fluid. Experiments are conducted for water at constant temperature with various flow rates to determine the heat transfer coefficients for flow in a tube. First the temperature of water is maintained at 35 C by temperature controller. After the steady state attains water is allowed to pass through the copper tube wounded with copper plate to measure the inlet and outlet temperatures of water. The fluid after passing through the copper tube is collected in the reservoir for recirculation. The volume flow rate of the working fluid, the inlet and outlet temperatures are noted down. The flow rate of the water is now 45

4 Heat Trasnfer Coefficient, h Heat Trasnfer Coefficient, h Heat Trasfer Coefficient, h varied (.2 l/min,.4 l/min,.6 l/min,.8 l/min) and the readings are noted down. Now the heater is switched on and the temperature is set to 4 C. After the set temperature is attained the water is again circulated and readings are noted down. DATA AND PROCESSING A.Thermo Physical Properties of Nanofluids The density of Al 2 O 3 /water nanofluid can be calculated using mass balance as ρ nf = (1 φ) ρ bf + φρ np (1) where ρ np and ρ bf are the densities of the nanoparticles and base fluid, respectively, and φ is volume concentration of nanoparticles. According to the concept of solid-liquid mixture, the specific heat of nanofluids is given by following Fluid Temperature at 4 C Volume Flow Rate, V +.1% Al2O3 Nanfluid Cp nf = (1 φ) ρ bf cp bf + φρ np cp np ρ nf (2) where cp np and cp bf are the heat specifics of the nanoparticles and base fluid, respectively. One well-known formula for computing the thermal conductivity of nanofluid is expressed in the following form: k nf = φ (3) k bf 4. RESULTS AND DISCUSSIONS In order to compare our experimental results with the values that are obtained for water and water +.1 % Al 2 O 3 Nanofluid, some graphs are plotted for which the experiment is conducted at different volume flow rates and at four different working fluid temperatures. Fig 4: Variation of heat transfer coefficient for different volume flow rates at 4 C Fluid Temperature at 45 C Volume Flow Rate, V +.1% Al2O3 Nanofluid Fig 5: Variation of heat transfer coefficient for different volume flow rates at 45 C Fig 3: Variation of heat transfer coefficient for different volume flow rates at 35 C Fluid Temperature at 5 C Fig 6: Variation of heat transfer coefficient for Volume flow rate, V different volume flow rates at 5 C +.1% Al2O3 Nanofluid 451

5 Heat Trasfer Rate, Q Heat Trasnfer Rate. Q Heat Trasnfer Rate. Q Fig. 6 Variation of heat transfer coefficient for different volume flow rates at 5 C Figure 3, 4, 5 and 6 shows the variation of heat transfer coefficient obtained experimentally for water and water +.1% Al 2 O 3 nanofluid with various volume flow rates and fluid temperature. It is seen that the heat transfer coefficient increases with volume flow rate. However from the figures it can be seen that the value of heat transfer coefficient of water +.1% Al 2 O 3 nanofluid is high for all temperatures and various volume flow rates as compared to heat transfer coefficient value of water for the same correlations. So it can be concluded that with increase in temperature with various volume flow rate, the heat transfer coefficient of water +.1% Al 2 O 3 nanofluid increases than water. In order to compare the heat transfer rate for water and water +.1 % Al 2 O 3 Nanofluid, some graphs are plotted for which the experiment is conducted at different volume flow rates and at four different working fluid temperatures. 1.5 volume flow rates at 4 C Fluid Temperature at 45 C Volume flow rate, V +.1% Al2O3 Nanofluid Fig 9: Variation of heat transfer rate for different volume flow rates at 45 C 1.5 Fluid Temperature at 5 C Volume flow rate, V +.1% Al2O3 Nanofluid Fig 1: Variation of heat transfer rate for different volume flow rates at 5 C Fig 7: Variation of heat transfer rate for different volume flow rates at 35 C 1.5 Fluid Temperature at 4 C Volume Flow Rate, V +.1% Al2O3 Nanfluid Fig 8: Variation of heat transfer rate for different Figure 7, 8, 9 and 1 shows the variation of heat transfer rate obtained experimentally for water and water +.1% Al 2 O 3 nanofluid with various volume flow rates and fluid temperature. It is seen that the heat transfer rate increases with volume flow rate. However from the figures it can be seen that the value of heat transfer rate of water +.1% Al 2 O 3 nanofluid is high for all temperatures and various volume flow rates as compared to heat transfer rate value of water for the same correlations. So it can be concluded that with increase in temperature with various volume flow rate, the heat transfer coefficient of water +.1% Al 2 O 3 nanofluid increases than water. 5. CONCLUSION The experiment is conducted to determine the heat transfer characteristics of Al 2 O 3 nanofluid in copper tube winded with copper plate at different volume flow rates and four different fluid temperatures 452

6 of 35, 4, 45 and 5 C. The same procedure is followed for base fluid (water) at the different correlations. The Reynolds Number increases with volume flow rate and is high for water +.1 % Al 2 O 3 nanofluid than water for the same temperature. But the Nusselt Number decreases with increase in volume flow rate and is low for water +.1 % Al 2 O 3 nanofluid than water. It is found that the heat transfer coefficient of water +.1 % Al 2 O 3 nanofluid increases with increasing volume flow rate It is also found that heat transfer rate of water +.1 % Al 2 O 3 nanofluid increases with flow rate of the fluid. Also the heat transfer coefficient and heat transfer rate of water +.1 % Al 2 O 3 nanofluid is high as compared to base fluid because the addition of.1 % volume concentration of Al 2 O 3 nanofluid increases the heat transfer characteristics of base fluid (water). But we found that the copper plate winded on the copper tube has a significant effect on the heat transfer. 6. REFERENCES [1] H. Almohammadi, Sh. Nasiri Vatan, E. Esmaeilzadeh, A. Motezaker, A. Nokhosteen Experimental Investigation of Convective Heat Transfer and Pressure Drop of Al 2 O 3 / Nanofluid in Laminar Flow Regime inside a Circular Tube. World Academy of Science, Engineering and Technology 68. [2] Abdulhassan Abd. K, Sattar Al-Jabair, Khalid Sultan Experimental Investigation of Heat Transfer and Flow of Nano Fluids in Horizontal Circular Tube. World Academy of Science, Engineering and Technology 61. [3] L. Syam Sundar,2 and K.V. Sharma Laminar Convective Heat Transfer and Friction Factor of AL 2 O 3 Nanofluid in Circular Tube Fitted with Twisted Tape.Inserts. International Journal of Automotive and Mechanical Engineering (IJAME) ISSN: (Print); ISSN: (Online); Volume 3, pp Developed Laminar Flow Regime. Journal of Heat and mass Transfer 52, pp [6] M. A. K. Chowdhuri1, R. A. Hossain, M.A.R. Sarkar An experimental investigation of turbulent flow heat transfer through tube with rodpin insert. International Journal of Engineering, Science and Technology. Vol. 3, No. 4, pp [7] S. Suresh, M. Chandrasekar, P. Selvakumar Experimental studies on heat transfer and friction factor characteristics of CuO/water nanofluid under laminar flow in a helically dimpled tube. Heat Mass Transfer (212) 48: DOI 1.17/s [8] P.K.Nagarajan and P.Sivashanmugam Heat Transfer Enhancement Studies in a Circular Tube Fitted with Right-Left Helical Inserts with Spacer. World Academy of Science, Engineering and Technology 58. [9] Kumbhar D.G., Dr. Sane N.K. 21. Heat Transfer Enhancement in a Circular Tube Twisted with Swirl Generator: A Review. Proc. of the 3rd International Conference on Advances In Mechanical Engineering, January 4-6, S.v. National Institute of Technology, Surat , Gujarat, India. [1] Saad A. El-Sayed*, Sayed A. EL-Sayed and Mohamed M. Saadoun Experimental Study of Heat Transfer to Flowing Air inside a Circular Tube with Longitudinal Continuous and Interrupted Fins. Journal of Electronics Cooling and Thermal Control, 212, 2, 1-16 doi: /jectc Published Online March. [11] K.B. Anoop, T. Sundararajan, S.K. Das, Effect of particle size on the convective heat transfer in nanofluid in the developing region, International Journal of Heat and Mass Transfer. 52 (29) [4] Heris, S.Z., Nasr Esfahany, M.,Etemad., and Gh.S., 27.Experimental Investigation of Convective Heat Transfer of Al 2 O 3 / Nanofluids in Circular Tube. International Journal of Heat and Fluid flow 28, pp [5] Hwang, K.S., Jang, S.P., and Choi, S.U.S., 29. Flow and Convective Heat Transfer Characteristic of - Based Al 2 O 3 Nanofluids in Fully 453