Experimental Investigation of Heat Transfer and Resistance Characteristics of a Finned Oval-Tube Heat Exchanger With Different Air Inlet Angles

Abstract A high accuracy of experimental correlations on the heat transfer and flow friction is always expected to calculate the unknown cases according to the limited experimental data from a heat exchanger experiment. However, certain errors will occur during the data processing by the traditional methods to obtain the experimental correlations for the heat transfer and friction. A dimensionless experimental correlation equation including angles is proposed to make the correlation have a wide range of applicability. Then, the artificial neural networks (ANNs) are used to predict the heat transfer and flow friction performances of a finned oval-tube heat exchanger under four different air inlet angles with limited experimental data. The comparison results of ANN prediction with experimental correlations show that the errors from the ANN prediction are smaller than those from the classical correlations. The data of the four air inlet angles fitted separately have higher precisions than those fitted together. It is demonstrated that the ANN approach is more useful than experimental correlations to predict the heat transfer and flow resistance characteristics for unknown cases of heat exchangers. The results can provide theoretical support for the application of the ANN used in the finned oval-tube heat exchanger performance prediction.

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Air inlet angle influence on the air-side heat transfer and flow friction characteristics of a finned oval tube heat exchanger

International Journal of Heat and Mass Transfer ◽

10.1016/j.ijheatmasstransfer.2019.118702 ◽

2019 ◽

Vol 145 ◽

pp. 118702 ◽

Cited By ~ 4

Author(s):

Linghong Tang ◽

Xueping Du ◽

Jie Pan ◽

Bengt Sundén

Keyword(s):

Heat Transfer ◽

Heat Exchanger ◽

Friction Characteristics ◽

Tube Heat Exchanger ◽

Flow Friction ◽

Air Inlet ◽

Inlet Angle ◽

Oval Tube

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An experimental investigation on air-side performances of finned tube heat exchangers for indirect air-cooling tower

Thermal Science ◽

10.2298/tsci1403863d ◽

2014 ◽

Vol 18 (3) ◽

pp. 863-874 ◽

Cited By ~ 5

Author(s):

Xueping Du ◽

Yantao Yin ◽

Min Zeng ◽

Pengqing Yu ◽

Qiuwang Wang ◽

...

Keyword(s):

Heat Transfer ◽

Heat Exchanger ◽

Heat Exchangers ◽

Cooling Tower ◽

Finned Tube ◽

Air Cooling ◽

Flat Tube ◽

Tube Heat Exchanger ◽

Air Inlet ◽

Oval Tube

A tremendous quantity of water can be saved if the air cooling system is used, comparing with the ordinary water-cooling technology. In this study, two kinds of finned tube heat exchangers in an indirect air-cooling tower are experimentally studied, which are a plain finned oval-tube heat exchanger and a wavy-finned flat-tube heat exchanger in a cross flow of air. Four different air inlet angles (90?, 60 ?, 45?, and 30?) are tested separately to obtain the heat transfer and resistance performance. Then the air-side experimental correlations of the Nusselt number and friction factor are acquired. The comprehensive heat transfer performances for two finned tube heat exchangers under four air inlet angles are compared. For the plain finned oval-tube heat exchanger, the vertical angle (90?) has the worst performance while 45? and 30? has the best performance at small ReDc and at large ReDc, respectively. For the wavy-finned flat-tube heat exchanger, the worst performance occurred at 60?, while the best performance occurred at 45? and 90? at small ReDc and at large ReDc, respectively. From the comparative results, it can be found that the air inlet angle has completely different effects on the comprehensive heat transfer performance for the heat exchangers with different structures.

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