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Heat and Mass Transfer Modeling and Simulation Part 7

Tham khảo tài liệu 'heat and mass transfer modeling and simulation part 7', kỹ thuật - công nghệ, cơ khí - chế tạo máy phục vụ nhu cầu học tập, nghiên cứu và làm việc hiệu quả | Heat and Mass Transfer in External Boundary Layer Flows Using Nanofluids 111 This parameter drawn in Figures 18 and 19 which is calculated within the thermal boundary layer evolves linearly along the wall. Strong differences are observed with the variation of the particle volume fraction. Fig. 18. Thermal flow rate for CuO water nanofluid Fig. 19. Thermal flow rate for Alumina water nanofluid 112 Heat and Mass Transfer - Modeling and Simulation To have a quantitative idea on how the thermal flow rate evolves with the particle volume fraction the parameter est is introduced Etfc - 1 100 30 Qthbf Fig. 20. Heat transfer coefficient at wall for CuO water nanofluid Fig. 21. Heat transfer coefficient at wall for Alumina water nanofluid Table 4 summarizes the evolution of this parameter with the particle volume fraction for both nanofluids traducing both heat and mass transfer in forced convection. It clearly appears that the thermal flow rate is strongly Ộ dependent. Heat and Mass Transfer in External Boundary Layer Flows Using Nanofluids 113 In comparison with the reference base fluid case an enhancement in the thermal flow rate is observed up to 42 for the CuO water nanofluid and 21 for the Alumina water nanofluid. CuO water nanofluid Alumina water nanofluid Volume fraction Pr A Sth Pr A Sth 0 6.984 0.402 0.00 6.984 0.402 0.00 1 8.006 0.383 9.64 7.222 0.397 2.28 2 6.860 0.404 -1.23 7.586 0.390 5.72 3 7.058 0.400 0.69 8.058 0.382 10.13 4 8.662 0.373 15.66 8.623 0.374 15.31 5 11.709 0.337 41.72 9.267 0.365 21.03 Table 4. Nanofluids properties in forced convection 5. Conclusion In the present study both free convection and forced convection problems of Newtonian CuO water and alumina water nanofluids over semi-infinite plates have been investigated from a theoretical viewpoint for a range of nanoparticle volume fraction up to 5 . The analysis is based on a macroscopic modelling and under assumption of constant thermophysical nanofluid properties. Whatever the thermal .