A genetic-algorithm-based experimental technique for determining heat transfer coefficient of exterior wall surface

2004 ◽  
Vol 24 (2-3) ◽  
pp. 339-349 ◽  
Author(s):  
Ling Zhang ◽  
Nan Zhang ◽  
Fuyun Zhao ◽  
Youming Chen
Keyword(s):  
Heat Transfer ◽  
Genetic Algorithm ◽  
Heat Transfer Coefficient ◽  
Transfer Coefficient ◽  
Experimental Technique ◽  
Wall Surface ◽  
Exterior Wall

Difference between the Measured and Theoretical Value and Theirs Influencing Factors for Heat Transfer Coefficient of Exterior Wall External Insulation

2011 ◽  
Vol 415-417 ◽  
pp. 1427-1430
Author(s):  
Yu Lan Tian ◽  
Jian Min Lu ◽  
Wen Yan Zhang
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Coefficient ◽  
Heat Flow ◽  
Transfer Coefficient ◽  
Exterior Wall ◽  
Flow Meter ◽  
External Insulation ◽  
Temperature Controlled ◽  
The Heat Transfer Coefficient ◽  
Heat Flow Meter

This paper analyzed the actual heat transfer coefficient of exterior wall external insulation, which was detected by temperature controlled hot box-heat flow meter method in Nanjing from March to December, 2010 .Research showed that: impacted by one-dimensional stability heat transfer assumption ,78.27% of test values of the heat transfer coefficient for exterior wall external insulation , are less than the calculated values; under certain circumstance, that the external thermal insulation material(Expandable polystyrene shutter, EPS board for short, and Extruded polystyrene shutter, XPS board for short)are the same, the more stable the wall substrate density and material , the greater the heat storage coefficient is and the smaller the relative detection error will be. When using the same stable wall substrate material, the calculation error of XPS board was significantly better than EPS board’s. The analysis, which is about error influence factors of test value of the heat transfer coefficient of exterior wall external insulation, shows that current temperature controlled hot box-heat flow meter heat transfer coefficient method needs further improved and perfect in order to improve the reliability of its conclusion.

Heat exchanger network retrofit throughout overall heat transfer coefficient by using genetic algorithm

2016 ◽  
Vol 94 ◽  
pp. 274-281 ◽  
Author(s):  
Totok Ruki Biyanto ◽  
Enrico Kevin Gonawan ◽  
Gunawan Nugroho ◽  
Ridho Hantoro ◽  
Hendra Cordova ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Genetic Algorithm ◽  
Heat Transfer Coefficient ◽  
Heat Exchanger ◽  
Transfer Coefficient ◽  
Heat Exchanger Network ◽  
Overall Heat Transfer Coefficient

scholarly journals Tip Clearance Effect on Heat Transfer and Leakage Flows on the Shroud-Wall Surface in an Axial Flow Turbine

1992 ◽  
Author(s):  
Masaya Kumada ◽  
Satoshi Iwata ◽  
Masakazu Obata ◽  
Osamu Watanabe
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Coefficient ◽  
Transfer Coefficient ◽  
Axial Flow ◽  
Local Heat Transfer ◽  
Local Heat ◽  
Local Heat Transfer Coefficient ◽  
Tip Clearance ◽  
Wall Surface ◽  
The Mean

An axial flow turbine for a turbocharger is used as a test turbine, and the local heat transfer coefficient on the surface of the shroud is measured under uniform heat flux conditions. The nature of the tip clearance flow on the shroud surface and a flow pattern in the downstream region of the rotor blades are studied, and measurements are obtained by using a hot-wire anemometer in combination with a periodic multi-sampling and an ensemble averaging technique. Data are obtained under on- and off-design conditions. The effects of inlet flow angle, rotational speed and tip clearance on the local heat transfer coefficient are elucidated. The mean heat transfer coefficient is correlated with the tip clearance, and the mean velocity is calculated by the velocity triangle method for approximation. A leakage flow region exists in the downstream direction beyond the middle of the wall surface opposite the rotor blade, and a leakage vortex is recognized at the suction side near the trailing edge.

Multi-Objective Optimization on the Fluid Flow and Heat Transfer of Semi-Attached Rib-Channels

2021 ◽  
Author(s):  
Xu Wang ◽  
Huazhao Xu ◽  
Jianhua Wang ◽  
Yuefeng Li ◽  
Wei Song
Keyword(s):  
Heat Transfer ◽  
Genetic Algorithm ◽  
Heat Transfer Coefficient ◽  
Transfer Coefficient ◽  
Optimization Method ◽  
Pressure Losses ◽  
Blade Cooling ◽  
Lower Heat ◽  
The Right ◽  
Rib Roughened

Abstract Rib-turbulators have been widely used in turbine blade cooling designs to enhance internal heat transfer. However, application of the ribs in blade cooling channels inevitably causes large pressure losses and lower heat transfer areas behind the ribs and at the joint parts of the ribbed wall with sidewalls in comparison to smooth channels. Semi-attached rib having two rectangular holes at the bottom of the ribs at the joint regions of the ribbed wall and two sidewalls is able to reduce friction losses and alleviates lower heat transfer in the channels. This paper presented a method of combining computational fluid dynamic simulation with an optimization method to optimize the performance of a channel with semi-attached ribs and to discuss the effects of hole geometric variables on both pressure losses and heat transfer enhancement. A fully automatic multi-objective genetic algorithm based on the Non-dominated Sorted Genetic Algorithm-II is applied for a one-pass squared channel with 60° inclined semi-attached ribs. Four geometrical variables are widths and heights of the two rectangular holes, and two objective functions are the maximum of area-averaged Nusselt number on the rib roughend wall and the minimum of friction factor. The Kriging model is constructed by using the Latin hypercube sampling method to choose 15 experimental points in the design space. The results showed that the optimization method helps to increase the channel performance and to eliminate nearly all low heat transfer areas by appropriately adjusting the heights and widths of the holes. Compared to solid ribs, the optimal semi-attached rib increases the area-averaged Nu number on the rib-roughened walls by 9.45%, whereas the friction factor in the channel is decreased by 6.95%, which corresponds to an increase of 12.13% in thermal performance. In the optimal model, the existence of large holes on the right side of the optimal semi-attached ribs moves the vortex core of the secondary flow downstream of the ribs from the right side of the solid-ribbed channel to the middle, which causes a large increase in Nu number on the middle and left side of the rib roughened walls and only a moderate reduction in Nu number on the right part of the walls. In the whole range discussed, heat transfer coefficient on the rib-roughened walls increased with the height of the right holes, but it increases with the width of the hole only in the range of 8–10mm. For the holes on the left, heat transfer coefficient deteriorates as the height and width increase. Increasing width and height of the holes on both sides of the semi-attached ribs reduces the channel friction losses.

A novel experimental technique to determine the heat transfer coefficient between the bed and particles in a downer

2013 ◽  
Vol 24 (2) ◽  
pp. 487-494 ◽  
Author(s):  
Yuji Yoshie ◽  
Masanori Ishizuka ◽  
Guoqing Guan ◽  
Chihiro Fushimi ◽  
Atsushi Tsutsumi
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Coefficient ◽  
Transfer Coefficient ◽  
Experimental Technique ◽  
The Heat Transfer Coefficient
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