Effect of using graphene/water based nanofluid on heat transfer in heat exchangers with rotating straight inner tube

Kerntechnik ◽  
2021 ◽  
Vol 86 (1) ◽  
pp. 50-63
Author(s):  
T. Koca
Keyword(s):  
Heat Transfer ◽  
Nusselt Number ◽  
Heat Exchanger ◽  
Heat Transfer Enhancement ◽  
Heat Exchangers ◽  
Pure Water ◽  
Water Volume ◽  
Transfer Enhancement ◽  
Tube Heat Exchanger ◽  
Nano Fluids

Abstract In this research, the effect of nanofluids including graphite and water on the heat transfer enhancement in heat Exchangers with both straight and rotational inner tube were examined. Nano-fluids including graphite and water were obtained at 0.01, 0.02 and 0.03 %volume concentrations by means of pure water as a base fluid. The aim of the study is to experimentally investigate and compare the influence of straight inner tube on the performance of a double tube heat exchanger at different flow rates, different capacity ratios (0.25, 0.5, 0.75, 1), different rotation rates (0 RPM, 100 RPM, 150 RPM, 200 RPM, 300 RPM, 500 RPM and 750 RPM) and by using nanofluid including graphite and water volume at values of 0.01, 0.02, 0.03%. In the experiments the flow is turbulent. In order to determine the heat transfer enhancement, the experimental datas were compared for pure water and nano-fluids. According to the results, Nusselt number, pressure loss, efficiency of heat exchanger were gauge. By the results achieved from experiments, correlations for Nusselt number have been reproduce and experimental data have been compared with ones in the literature by drawing graphics. The experiment that provides the best increase in heat transfer is the nanofluid including 0.02% volume concentrations of graphene/water at 500RPM speed.

Heat transfer enhancement for fin-tube heat exchanger using vortex generators

2002 ◽  
Vol 16 (1) ◽  
pp. 109-115 ◽  
Author(s):  
Seong-Yeon Yoo ◽  
Dong-Seong Park ◽  
Min-Ho Chung ◽  
Sang-Yun Lee
Keyword(s):  
Heat Transfer ◽  
Heat Exchanger ◽  
Heat Transfer Enhancement ◽  
Vortex Generators ◽  
Transfer Enhancement ◽  
Tube Heat Exchanger ◽  
Fin Tube

Numerical Investigation of Heat Transfer Enhancement Using Hybrid Vortex Generator Arrays in Fin-and-Tube Heat Exchangers

2016 ◽  
Vol 8 (3) ◽  
Author(s):  
Shubham Agarwal ◽  
R. P. Sharma
Keyword(s):  
Heat Transfer ◽  
Heat Exchanger ◽  
Heat Transfer Enhancement ◽  
Heat Exchangers ◽  
Numerical Study ◽  
Vortex Generator ◽  
Roll Angle ◽  
Transfer Enhancement ◽  
Maximum Heat ◽  
Hybrid Configuration

This is a novel study for assessing the heat transfer enhancement in a multi-row inline-tube heat exchanger using hybrid vortex generator (VG) arrays, i.e., rectangular winglet pairs (RWPs) with different geometrical configurations installed in coherence for enhanced heat transfer. The three-dimensional numerical study uses a full scale seven-tube inline heat exchanger model. The effect of roll of rectangular winglet VG on heat transfer enhancement is analyzed and optimized roll angle is determined for maximum heat transfer enhancement. Four different configurations are analyzed and compared in this regard: (a) single RWP (no roll); (b) 3RWP-inline array(alternating tube row with no roll of VGs); (c) single RWP (with optimized roll angle VGs); and (d) 3RWP-inline array(alternating tube row with all VGs having optimized roll angle). It was found that the inward roll of VGs increased the heat transfer from the immediately downstream tube but reduced heat transfer enhancement capability of other VG pairs downstream. Further, four different hybrid configurations of VGs were analyzed and the optimum configuration was obtained. For the optimized hybrid configuration at Re = 670, RWP with optimized roll angle increased heat transfer by 17.5% from the tube it was installed on and by 42% from the immediately downstream tube. Increase in j/ƒ of 36.7% is obtained by use of hybrid VGs in the optimized hybrid configuration. The deductions from the current study are supposed to well enhance the performance of heat exchangers with different design configurations.

scholarly journals Investigation of Fin Spacing for Heat Transfer Enhancement in Cross Flow Over Tubes Between Two Parallel Plates

2019 ◽  
Vol 2 (1) ◽  
Author(s):  
Ahmad Nurye Oumer ◽  
Amer Farhan Alias
Keyword(s):  
Heat Transfer ◽  
Heat Flux ◽  
Heat Exchanger ◽  
Heat Transfer Enhancement ◽  
Parallel Plates ◽  
Transfer Enhancement ◽  
Tube Heat Exchanger ◽  
Finned Tube Heat Exchanger ◽  
Different Types ◽  
Fin Spacing

This research explains the investigation of fin spacing for heat transfer enhancement in the finned tube heat exchanger. The objective of this paper is to recommend the optimum fin spacing for heat transfer enhancement. Three different types of tube and spacing are identified through the simulation from Ansys software. The data between simulation using Ansys Fluent and published literature were being compared. Graph of total pressure, Nusselt number and total temperature have been plotted to make the comparison. Result obtained showed that were a bigger agreement between the simulation and published literature for both types of the tube which are circular and elliptic. From the analysis, there were considered two types of arrangement for the different types of tube. From that, the aligned arrangement is the best for heat transfer enhancement compared to the staggered. For the effect of spacing, there was three spacing which is 1.7 mm, 1.8 mm, and 2.0 mm spacing with velocity and the total heat flux is set to be constant (v =1.4 m/s; q = 500 W/m2). For the circular tube, it can be seen that the wider of the fin spacing gave the best heat transfer enhancement in the heat exchanger. Different from the circular which is 1.8 mm spacing is the best for heat transfer enhancement. Other types of tube are a flat surface which is comparing with the variations of Nu vs Re with different heat flux. Then, the result showed that as the Re is increased the Nu will also increase. In the other side, it is recommended for future work to do the real model dimension followed to import to the Ansys instead of assuming the model is symmetrical.

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