Effect of non-uniform heat flux on wall friction and convection heat transfer coefficient in a trapezoidal channel

2001 ◽  
Vol 44 (13) ◽  
pp. 2453-2459 ◽  
Author(s):  
T.J. Remley ◽  
S.I. Abdel-Khalik ◽  
S.M. Jeter ◽  
S.M. Ghiaasiaan ◽  
M.F. Dowling
Keyword(s):  
Heat Transfer ◽  
Heat Flux ◽  
Heat Transfer Coefficient ◽  
Transfer Coefficient ◽  
Convection Heat Transfer ◽  
Wall Friction ◽  
Uniform Heat Flux ◽  
Convection Heat ◽  
Convection Heat Transfer Coefficient ◽  
Trapezoidal Channel

Experimental Study of Local Heat Transfer Coefficient of R113 Flow Boiling in Vertical Square Tube

2011 ◽  
Vol 374-377 ◽  
pp. 622-625
Author(s):  
Wei Sun ◽  
Ya Jun Guo ◽  
Qin Cheng Bi ◽  
Bin Gao ◽  
Ying Kun Xu
Keyword(s):  
Heat Transfer ◽  
Heat Flux ◽  
Heat Transfer Coefficient ◽  
Transfer Coefficient ◽  
Flow Boiling ◽  
Convection Heat Transfer ◽  
Equivalent Diameter ◽  
Convection Heat ◽  
Convection Heat Transfer Coefficient ◽  
Steam Quality

This article is based on the experimental investigations on flow boiling heat transfer of R113 with the equivalent diameter of the square tube 15.66mm, mass flow rate 500 ~ 2000kg / (m2•s), steam quality from 0.1 to 1, heat flux 50 ~ 90kW/m2, and pressure 100 ~ 250 kPa. The experimental results show that with the rise of heat flux and mass velocity the local convection heat transfer coefficient increases, and with the enhancement of steam quality the local convection heat transfer coefficient increases firstly and then decreases. By comparison of the experimental data and the calculation results of predecessor’s correlations, a correction coefficient applicable to this experiment was obtained.

Inverse Heat Transfer Analysis of Grinding, Part 2: Applications

1996 ◽  
Vol 118 (1) ◽  
pp. 143-149 ◽  
Author(s):  
C. Guo ◽  
S. Malkin
Keyword(s):  
Heat Transfer ◽  
Heat Flux ◽  
Heat Transfer Coefficient ◽  
Transfer Coefficient ◽  
Convection Heat Transfer ◽  
Contact Length ◽  
Heat Transfer Analysis ◽  
Convection Heat ◽  
Convection Heat Transfer Coefficient ◽  
Inverse Heat Transfer

Distributions of the heat flux to the workpiece and the convection heat transfer coefficient on the workpiece surface during straight surface grinding are estimated from measured temperatures in the workpiece subsurface using inverse heat transfer methods developed in Part 1. The results indicate that the heat flux to the workpiece is distributed approximately linearly (triangular heat source) along the grinding zone with about 70 to 75 percent of the total energy transported as heat to the workpiece for grinding of steels with a conventional aluminum oxide wheel and only about 20 percent with CBN superabrasive wheels. The wheel-workpiece contact length corresponding to the region of positive heat flux to the workpiece is found to be generally close to but slightly longer than the theoretical geometric contact length. The convection heat transfer coefficient for cooling by the applied grinding fluid is greatest just behind the trailing edge of the grinding zone where fluid is directly applied, and negligible ahead of the grinding zone.

scholarly journals Experimental and Theoretical Investigation of the Natural Convection Heat Transfer Coefficient in Phase Change Material (PCM) Based Fin-and-Tube Heat Exchanger

Energies ◽  
2021 ◽  
Vol 14 (3) ◽  
pp. 716
Author(s):  
Saulius Pakalka ◽  
Kęstutis Valančius ◽  
Giedrė Streckienė
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Coefficient ◽  
Natural Convection ◽  
Energy Storage ◽  
Heat Exchanger ◽  
Transfer Coefficient ◽  
Convection Heat Transfer ◽  
Natural Convection Heat Transfer ◽  
Convection Heat ◽  
Convection Heat Transfer Coefficient

Latent heat thermal energy storage systems allow storing large amounts of energy in relatively small volumes. Phase change materials (PCMs) are used as a latent heat storage medium. However, low thermal conductivity of most PCMs results in long melting (charging) and solidification (discharging) processes. This study focuses on the PCM melting process in a fin-and-tube type copper heat exchanger. The aim of this study is to define analytically natural convection heat transfer coefficient and compare the results with experimental data. The study shows how the local heat transfer coefficient changes in different areas of the heat exchanger and how it is affected by the choice of characteristic length and boundary conditions. It has been determined that applying the calculation method of the natural convection occurring in the channel leads to results that are closer to the experiment. Using this method, the average values of the heat transfer coefficient (have) during the entire charging process was obtained 68 W/m2K, compared to the experimental result have = 61 W/m2K. This is beneficial in the predesign stage of PCM-based thermal energy storage units.

Thermal Response Characteristics of Flat Plate Heated by High Temperature and High Speed Flow

2013 ◽  
Vol 448-453 ◽  
pp. 3316-3319
Author(s):  
Chuang Sun ◽  
Yang Zhao ◽  
De Fu Li ◽  
Qing Ai ◽  
Xin Lin Xia
Keyword(s):  
Heat Transfer ◽  
Temperature Field ◽  
Heat Transfer Coefficient ◽  
Transfer Coefficient ◽  
Flat Plate ◽  
High Speed ◽  
Convection Heat Transfer ◽  
Thermal Response ◽  
Convection Heat ◽  
Convection Heat Transfer Coefficient

According to the view of heat transfer, the process of the fluid flow with high temperature and high speed over a flat plate may be considered as the heat transfer process within a compressible thermal boundary layer. Based on the numerical results of thermal isolation assumption, combining the temperature comparison with modification method, a coupled method of convection heat transfer coefficient with temperature field of the plate is established, and the characteristics of the thermal response for the flat plate is dominated. Take some ribbed plates as instances, the convection heat transfer coefficient and temperature field of the plate are simulated through the provided coupled method. The results show that, not only the position and materials of the plate influence the convection heat transfer coefficient, but also the time.

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