Hybrid Al2O3-Cu/water nanofluid flow and heat transfer over vertical double forward-facing step

Abstract

Turbulent heat transfer and hybrid Al2O3-Cu/nanofluid over vertical double forward facing-stepis numerically conducted. K-? standard model based on finite volume method in two dimensional are applied to investigate the influences of Reynolds number, step height, volume fractions hybrid Al2O3-Cu/nanofluid on thermal performance. In this paper, different step heights for three cases of vertical double FFS are adopted by five different of volume fractions of hybrid (Al2O3-Cu/water) nanofluid varied for 0.1, 0.33, 0.75, 1, and 2, while the Reynolds number different between 10000 to 40000 with temperature is constant. The main findings revealed that rise in local heat transfer coefficients with raised Reynolds number and maximum heat transfer coefficient was noticed at Re=40000. Also rises in heat transfer coefficient detected with increased volume concentrations of hybrid (Al2O3-Cu/water) nanofluid and the maximum heat transfer coefficient found at hybrid Al2O3-Cu/water nanofluid of 2% in compared with others. It?s also found that rise in surface heat transfer coefficient at 1ststep-case 2 was greater than at 1ststep-case 1 and 3 while was higher at 2ndstep-case 3. Average heat transfer coefficient with Reynolds number for all cases are presented in this paper and found that the maximum average heat transfer coefficient was at case 2 compared with case 1 and 3. Gradually increases in skin friction coefficient remarked at 1stand 2ndsteps of the channel and drop in skin friction coefficient was obtained with increased of Reynolds number. Counter of velocity was presented to show the recirculation regions at first and second steps as clarified the enrichment in heat transfer rate. Furthermore, the counter of turbulence kinetic energy contour was displayed to provide demonstration for achieving thermal performance at second step for all cases.

3D Numerical simulation of turbulent heat transfer and Fe3O4/nanofluid annular flow in sudden enlargement

“…Also Augmentation in heat transfer was noticed by effect of contraction ratio and maximum improvement was found at contraction ratio of 1 as described by Hakan et al [3]. Modification in transport pipeline has significant effect on thermal performance such as expanding or contracting in passage, ribbed channel, and used fins are examined in numerous numerical and experimental researches [4][5][6][7][8][9][10][11][12][13][14][15][16][17][18]. In the last two decades, many researches are used nanofluids as alternative fluids due to it have been greater thermal conductivity compared to normal fluids [19][20][21][22][23][24][25][26][27][28].…”

Convective Heat Transfer in a Three-Dimensional Tubular Exchanger Filled with Pure/Hybrid Water-Based Nanofluid and Exposed to the Magnetic Field Effects

“…In addition, to meet industrial requirements in terms of reliability and durability, heat exchangers have undergone several innovations in the geometric structure. Moreover, to assess the performance of nanofluids in heat exchange, several tests have been carried out on suspension of pure [1,2,[9][10][11][12] and hybrid water-based nanoparticle [6,[13][14][15][16]. To highlight the performance of nanofluids in this area, it is important, to look at the previous works;…”

“…So, to ensure the reliability of traction motors, automotive heat exchanger need to transfer heat more efficiently. This survey may be completed by subjecting the nanofluids to the effects of magnetic fields [4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19]. This test is dedicated to control the heat transfer stability and to master flow viscosity and friction.…”