Numerical simulation of heat transfer performance of R410A in condensing-superheated zone

2021 ◽  
Author(s):  
Lu Zhang ◽  
Jinping Liu ◽  
Xiongwen Xu
Keyword(s):  
Heat Transfer ◽  
Numerical Simulation ◽  
Heat Transfer Performance ◽  
Transfer Performance

Effect of Protuberances in the Heat Transfer Enhancement in Mini-Channels

2021 ◽  
Author(s):  
Ariel Cruz Diaz ◽  
Gerardo Carbajal
Keyword(s):  
Heat Transfer ◽  
Numerical Simulation ◽  
Pressure Drop ◽  
Heat Transfer Enhancement ◽  
Heat Transfer Performance ◽  
Heat Removal ◽  
Working Fluid ◽  
Transfer Performance ◽  
Transfer Enhancement ◽  
Mini Channels

Abstract This study presents the effects of adding an array of protrusions in a microchannel for heat transfer enhancement. The presence of mini-channels increases the overall heat transfer area and boosts the mixing development near the solid-fluid interaction; therefore, it can remove more heat than conventional mini-channels without protuberances. A numerical study proved that protuberances in a mini-channel increase the heat transfer performance by disturbing the relative fluid motion near the solid wall. The numerical simulation was performed with three different protuberances arrays: aligned, staggered, and angular. Each array consists of a thin flat plate with a hemispherical shape; the working fluid and the solid materials were water and copper. The study also includes the effect of different Reynolds numbers: 1,000, 1,500, and 2,000. Three heat inputs were applied in the numerical simulation; these were 1W, 3W, and 5W. The study was compared with a simple microchannel with non-protuberances to analyze the microchannel performance regarding heat removal and pressure drop. For heat transfer performance, the best array was the staggering array with a maximum heat removal increase of 5.26 percent. In terms of pressure drop performance, the best array was the aligned array, with a maximum increase of 34.73 percent.

Structure Size on the Heat Transfer Performance of Shell and Tube Heat Exchanger

2015 ◽  
Vol 778 ◽  
pp. 37-40
Author(s):  
Mei Jin ◽  
Li Zhan ◽  
Han Lin Wu ◽  
Hong Jiao Liu
Keyword(s):  
Heat Transfer ◽  
Numerical Simulation ◽  
Heat Transfer Performance ◽  
Transfer Performance ◽  
Baffle Plate ◽  
Tube Heat Exchanger ◽  
F Factor ◽  
Shell And Tube ◽  
Simulation Results ◽  
Gap Height

In this paper, based on the numerical simulation with RNG k-ε model by using commercial code of FLUENT, the effects of the structure size of the shell and tube heat exchanger, such as the baffle spacing and the gap height of baffle plate, on the pressure drop, the heat transfer coefficient and j-f Factor were investigated to obtain the relationship between the baffle spacing and the gap height of baffle plate using the same thermophysical conditions. The numerical simulation results exhibited that there was a non-monotonic relationship between the baffle spacing and the gap height of baffle plate. A better heat transfer performance could be observed under the condition of a smaller value of the baffle spacing and a higher value of the ratio of the gap height to the actual section, or under the condition of a higher value of the baffle spacing and a smaller value of the ratio of the gap height to the actual section. Moreover, under the optimum geometrical condition, the numerical simulation results showed that a smaller difference between the inlet section length and the baffle spacing could give a higher j-f Factor and a better heat transfer performance.

Laminar Heat Transfer Performances in a Tube with Center-Cleared Twisted Tape of Alternate Axes

2014 ◽  
Vol 1070-1072 ◽  
pp. 1803-1807
Author(s):  
Li Xiang Chen
Keyword(s):  
Heat Transfer ◽  
Numerical Simulation ◽  
Nusselt Number ◽  
Heat Transfer Performance ◽  
Twisted Tape ◽  
Transfer Performance ◽  
Performance Evaluation Criterion ◽  
Twisted Tapes ◽  
Tubular Flow ◽  
Underlying Mechanisms

To improve the heat transfer performance of laminar tubular flow, a center-cleared twisted tape of alternate axes was developed as inserts. Numerical simulation was conducted to investigate the effect of dislocation angle of twisted tapes on the thermo-hydraulic performances. The numerical results show that, the largest Nusselt number occurs at a dislocation angle of 60°. The friction factorfis relatively larger than that when the dislocation angle is 0°, and it exhibits an obvious increment with the dislocation angle. From the value of performance evaluation criterion (PEC), the best thermo-hydraulic performance is achieved at a 60° dislocation angle. The underlying mechanisms are analyzed in terms of flow field and temperature field.

Numerical Investigation on Flow and Heat Transfer in Matrix Cooling Channels for Turbine Blades

2016 ◽  
Author(s):  
Yigang Luan ◽  
Shi Bu ◽  
Haiou Sun ◽  
Tao Sun
Keyword(s):  
Heat Transfer ◽  
Numerical Simulation ◽  
Pressure Drop ◽  
Heat Transfer Performance ◽  
Structural Parameters ◽  
Turbine Blades ◽  
Channel Width ◽  
Transfer Performance ◽  
Cooling Channel ◽  
Cooling Channels

Matrix cooling is one kind of internal cooling structures applied to protect turbine blades. This paper investigated the flow field and heat transfer performance in matrix cooling channels experimentally and numerically. A testing section (rib angle of 45-deg, rib thickness of 30mm, rib height of 30mm and sub-channel width of 30mm) made of Plexiglas was build and connected to a wind tunnel sysytem. And Transient Liquid Crystal (TLC) technique was applied to obtain the detailed heat transfer distribution on the primary surface inside the matrix cooling channel. The experiment was performed under different Reynolds numbers varying from 18428 to 28327, based on the channel inlet hydraulic diameter; also the overall pressure drop across the channel was measured. Experimental results were used to calibrate the numerical solution obtained by computational fluid dynamics (CFD) method. During the numerical simulation process, structured grids and k-w turbulence model was employed. And a good agreement is obtained between experimental and CFD results for both pressure drop and heat transfer performance. Channels of various structural parameters (rib angle, rib thickness and sub-channel width) were then studied by numerical simulation, three rib angles (30-deg, 45-deg and 60-deg), three rib thicknesses (1.8mm, 3mm and 5mm) and three sub-channel widths (3mm, 5mm and 9mm) were considered, with the rib height 3mm for all the cases. Numerical results showed that the sidewall turnings made the greatest contribution to heat transfer enhancement but caused very large pressure drop meanwhile. The overall heat transfer and pressure drop increase with rib angle and rib width but decrease with sub-channel width. The thermal performance factor decreases with rib angle and rib width, while it showed a non-monotonic dependency on sub-channel width. Among the three structural parameters, rib angle has the most significant effect on the performance of matrix cooling channel.

scholarly journals Numerical Simulation of Solid and Porous Fins’ Impact on Heat Transfer Performance in a Differentially Heated Chamber

Mathematics ◽  
2022 ◽  
Vol 10 (2) ◽  
pp. 263
Author(s):  
Le Xuan Hoang Khoa ◽  
Ioan Pop ◽  
Mikhail A. Sheremet
Keyword(s):  
Heat Transfer ◽  
Numerical Simulation ◽  
Heat Transfer Performance ◽  
Energy Transport ◽  
Heated Wall ◽  
Transfer Performance ◽  
Finite Difference Technique ◽  
Good Technique ◽  
Vertical Walls ◽  
Porous Fins

The development of different industrial fields, including mechanical and power engineering and electronics, demands the augmentation of heat transfer in engineering devices. Such enhancement can be achieved by adding extended heat transfer surfaces to the heated walls or heat-generating elements. This investigation is devoted to the numerical analysis of natural convective energy transport in a differentially heated chamber with isothermal vertical walls and a fin system mounted on the heated wall. The developed in-house computational code has been comprehensively validated. The Forchheimer–Brinkman extended Darcy model has been employed for the numerical simulation of transport phenomena in a porous material. The partial differential equations written, employing non-primitive variables, have been worked out by the finite difference technique. Analysis has been performed for solid and porous fins with various fin materials, amounts and heights. It has been revealed that porous fins provide a very good technique for the intensification of energy removal from heated surfaces.

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