IRJET- CFD Analysis of Double Pipe Heat Exchanger with Different Inner Sections
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This document analyzes the heat transfer performance of a double pipe heat exchanger with circular and square inner sections using computational fluid dynamics (CFD). CFD simulations were conducted using ANSYS Fluent to analyze temperature contours and heat transfer rates. The results showed that the square inner section heat exchanger absorbed more heat from the hot fluid and had a higher heat flow rate than the circular section design, with the cold fluid outlet temperature being higher for the square section. In conclusion, the square inner section design exhibited better heat transfer performance compared to the conventional circular section design for this type of heat exchanger.
IRJET- CFD Analysis of Double Pipe Heat Exchanger with Different Inner Sections
- 1. International Research Journal of Engineering and Technology (IRJET) e-ISSN: 2395-0056 Volume: 05 Issue: 04 | Apr-2018 www.irjet.net p-ISSN: 2395-0072 © 2018, IRJET | Impact Factor value: 6.171 | ISO 9001:2008 Certified Journal | Page 1851 CFD ANALYSIS OF DOUBLE PIPE HEAT EXCHANGER WITH DIFFERENT INNER SECTIONS Hariraam.V1, Domnic Edward.D2, Gokula Krishnan.M3, Dombega Shivajittu4, Selvan.P5 1,2,3,4 Student of B.E Mechanical Engineering, SNS College of Engineering, Coimbatore, India 5 Under the Guidance of Assistant Professor, Department of Mechanical Engineering, SNS College of Engineering, Coimbatore, India ---------------------------------------------------------------------***--------------------------------------------------------------------- Abstract - Heat transfer techniques and thermalproperties of Heat Exchanger can be analyzed usingComputationalFluid Dynamics tools. There exists no analysiswithvaryingtheinner section, tube of double piped heat exchanger with square as a substitute for conventional circular section. The methodology for CFD analysis of a heat exchanger is validatedistheeffectof fluid properties for both square and circle sections are with constant temperatureandthermalpropertieswhereanalyzed. The contour of temperature for both the circular and square sections are calculated using ANSYS fluent 15.0, Where the equation of mass, moment and heat transfer where solved simultaneously using k- epsilon two equation turbulence mode. Thus, this research results in better selection of inner section for double pipe heat exchanger. Key Words: Heat Exchanger, Computational Fluid Dynamics, Varying Inner Sections, Circle, Square. 1. INTRODUCTION Heat exchanger plays an important in power plantsandheat recovery units. Due to increasing the population, the energy is efficient for our daily works. So thatmanyheatexchangers can be used for utilize the energy efficiently. Here analyzing the heat transfer between two fluids such as hot and cold. In this paper the circle and squareshapeofheatexchangerpipe was analyzed for which one is maximum heat transfer rate. The analysis is done by the computational fluid dynamics in the software of ANSYS fluent 15.0. The flow analysis is set between hot and cold water passing the pipe. The velocityof hot water is less when compared to the cold water in order to increase the heat transfer rate. The heat transfer coefficient is critical for designing anddevelopingtheflow of process. 1.1 Types of Heat Exchanger There are innumerable types of heat exchangers are available in use such as Tubular type heat exchanger, Plate type heat exchanger, Extendedheat exchanger,Regenerative heat exchanger. Here the Tubular type Double Pipe Heat Exchanger is analyzed. 2. INPUT PARAMETERS 2.1 Double pipe Heat Exchanger with Inner Circular Section 2.1.1.Calculation for Inner Circular Section Diameter, d = 0.06m Area, a =(πd2)/4 =2.82×10-3 m2 Velocity , v = 0.003m/s Hydraulic diameter, Hd = (4A/P) =0.06m Mass flow rate, m = ρ.A.V = 0.01 kg/s 2.1.2.Calculation for outer section – Cylinder Area, A = 7.4612×10-3 m2 Velocity, V = 0.004m/s Mass flow rate, m = ρ.A.V = 0.029Kg/s Fig-1: Solid Model of Double pipe Heat Exchanger with inner Circular Tube modeled using SOLIDWORKS 2.2.Double pipe Heat Exchanger with Inner Square Section 2.2.1 Calculation for Inner Section Square: Hydraulic Diameter, Dh = 0.06m Area, A = a2
- 2. International Research Journal of Engineering and Technology (IRJET) e-ISSN: 2395-0056 Volume: 05 Issue: 04 | Apr-2018 www.irjet.net p-ISSN: 2395-0072 © 2018, IRJET | Impact Factor value: 6.171 | ISO 9001:2008 Certified Journal | Page 1852 Perimeter, P = 4a Side, a 0.06 = (4A/P) 0.06 = (4×a2)/4a a = 0.06m Mass flow rate, m = ρ.A.V = 0.0108 Kg/s 2.2.2 Calculation for Outer section – Cylinder Area, A = 6.409×10-3 m2 Velocity, V = 0.004m/s Mass flow rate, m = ρ.A.V = 0.0256Kg/s Fig-2: Solid Model of Double pipe Heat Exchanger with inner Square Tube modeled using SOLIDWORKS. 3. SOLUTION STRATEGY & CONVERGENCE The mesh made is with small mesh sizes, so good gradients can be obtained in boundaries. The values in the table indicate the properties of circular, Square inner pipe. Fig-3: Double pipe Heat Exchanger Circular Tube with Mesh Fig - 4: Double pipe Heat Exchanger Square Tube with Mesh Table – 1: Details of Mesh Model Details Circular Section Square Section Nodes 33425 9900 Element 31350 9047 4. VALIDATION OF MODEL The circular and square tube was analysed using computational fluid dynamics for counter flow where hot fluid flows through the inner pipe and the cold fluid flows through the outer pipe. Heat transfer parameters, such as temperature drop was calculated. Thus simulation results were developed. The simulation results of the circular tube were compared with the results obtained for a square tube of equal length and similar operating conditions in order to compare its performance related to thermal properties of the heat exchangers. Table – 2: CFD Validation Parameters Type of Inner Section CIRCLE SQUARE Length 1m 1m Hydraulic Diameter 0.06m 0.06m Working Fluid WATER – LIQUID WATER – LIQUID Cold Fluid Inlet Temperature 303 K 303 K Hot Fluid Inlet Temperature 350 K 350 K Mass Flow Rate 0.01 Kg/s 0.0108 Kg/s
- 3. International Research Journal of Engineering and Technology (IRJET) e-ISSN: 2395-0056 Volume: 05 Issue: 04 | Apr-2018 www.irjet.net p-ISSN: 2395-0072 © 2018, IRJET | Impact Factor value: 6.171 | ISO 9001:2008 Certified Journal | Page 1853 5. RESULT CFD computations were done for the mass flow rate of water 0.01 circular tube and 0.0108 kg/s for square tube. Performance parameters adopted for comparison are heat pick range by the cold fluid and heat flow rate. The heat transfer in the circular tube in analysed in ANSYS FLUENT as fig- 5 and the results fig - 6 are obtained. Fig – 5: Temperature Contour of Circular tube Fig – 6: Results of Static Temperature The heat transfer in the square tube in analysed in ANSYS FLUENT as fig 7and the results fig 8 are obtained. Fig -7: Temperature Contour of Square tube Fig – 8: Results of Static Temperature Table – 3: Comparison of Working Fluid Temperature Type of Inner Section Circle Square Cold Fluid inlet Tempeature 303 K 303 K Cold Fluid outlet Tempeature 314.27 K 316.78 K HotFluid inlet Tempeature 350 K 350 K Cold Fluid outlet Tempeature 331.73 K 333.09 K Heat Flow rate ,Q 1366.808 W 1475.274 W From the results, the cold fluid outlet temperature is higher in square tube than the conventional circular tube. Thus, the Heat absorbed by the cold fluid from the hot fluid is more in square tube than the conventional circular tube. Chart – 1: Temperature Difference of Cold Fluid (Heat pick up range) in different inner sections. The heat flow rate of cold fluid for circle tube is 1366.80W The heat flow rate of hot fluid for square tube is 1475.27W.
- 4. International Research Journal of Engineering and Technology (IRJET) e-ISSN: 2395-0056 Volume: 05 Issue: 04 | Apr-2018 www.irjet.net p-ISSN: 2395-0072 © 2018, IRJET | Impact Factor value: 6.171 | ISO 9001:2008 Certified Journal | Page 1854 The heat flow rate of cold fluid for circle tube and square tube is plotted as a graph shows in the Chart 2. Chart - 2: Heat Flow Rate of Cold Fluid in different inner sections 6. CONCLUSION Comparing with the circular and square, theheatpick ratein the cold fluid done by the square section is more in the counter flow. The heat flow rate is high due to high end turbulent edges are more when compared to circle. TheCFD software have emerged as a cost effective and speedy solution provider to heat exchanger design, analysis and optimization. In squarecornerswerepresent whilethecircle has no corners, When the number of corners increases the heat dissipation at the corners are also increases. So the net heat flow rate also increases. REFERENCES 1. Muhammad Mahmood Aslam Bhutta et al, CFD applications in various heat exchangers design: A review, Applied Thermal Engineering, 32 (2012), Page No.1-12. 2. M.Z.M.Saqheeb Ali et al,Thermal Analysis of Double Pipe Heat Exchanger by Changing the Materials Using CFD, International Journal of Engineering Trends and Technology (IJETT) – Volume 26 Number 2- August 2015 Page no. 95-102 3. Kale Shivam B et al, Experimental analysis & Simulation of double pipe heat Exchanger, IJARIIE- ISSN(O)-2395-4396, Vol-3 Issue-2 2017 I 4. Dr.Y.Krishna et al,CFD Analysis and Performance of Parallel and counter flow in Concentric tube heat Exchanger, International Journal of Engineering Technology and research Vol-2, Issue -11, Novermber 2017, Page No. 2782-2792.