Prediction of Two-Phase Heat Transfer Coefficients in a Horizontal Pipe for Different Inclined Positions With Artificial Neural Networks

2015 ◽  
Vol 137 (6) ◽  
Author(s):  
Najmeh Sobhanifar ◽  
Ebrahim Ahmadloo ◽  
Sadreddin Azizi
Keyword(s):  
Neural Network ◽  
Heat Transfer ◽  
Experimental Data ◽  
Neural Networks ◽  
Two Phase Flow ◽  
Reynolds Numbers ◽  
Phase Flow ◽  
Transfer Coefficients ◽  
Two Phase ◽  
Heat Transfer Coefficients

This paper presents the application of artificial neural network (ANN) in prediction of heat transfer coefficients (HTCs) of two-phase flow of air–water in a pipe in the horizontal and slightly upward inclined (2, 5, and 7 deg) positions. For this purpose, the superficial liquid and gas Reynolds numbers and the inclination of the pipe were used as input parameters, while the HTCs of two-phase flow were used as output parameters in training and testing of the multilayered, feedforward, backpropagation neural networks. In this present study, experimental data were taken from literature and then used for the ANN model. The superficial liquid and gas Reynolds numbers ranged from 740 to 26,100 and 560 to 47,600 for water and air, respectively. The mean deviations against experimental data were determined for the model. Results showed that the network predictions were in very good agreement with the experimental HTC data, whereas the correlation showed more deviations. Finally, results showed that the accuracy between the neural network predictions and experimental data was achieved with mean relative error (MRE) of 2.92% and correlation coefficient (R) that was 0.997 for all datasets, which suggests the reliability of the ANNs as a strong tool for predicting HTCs with two-phase flows.

scholarly journals Two-dimensional heat transfer coefficients with simultaneous flow visualisations during two-phase flow boiling in a PDMS microchannel

2018 ◽  
Vol 130 ◽  
pp. 624-636 ◽  
Author(s):  
Sofia Korniliou ◽  
Coinneach Mackenzie-Dover ◽  
John R.E. Christy ◽  
Souad Harmand ◽  
Anthony J. Walton ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Two Phase Flow ◽  
Flow Boiling ◽  
Phase Flow ◽  
Two Dimensional ◽  
Transfer Coefficients ◽  
Two Phase ◽  
Heat Transfer Coefficients ◽  
Pdms Microchannel

scholarly journals Two-phase flow pattern and heat transfer coefficients of R245fa/R134a under non-uniform heat flux

2019 ◽  
Vol 65 (17) ◽  
pp. 1741-1751
Author(s):  
Yani Lu ◽  
Li Zhao ◽  
Shuai Deng ◽  
Dongpeng Zhao ◽  
Xianhua Nie ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Heat Flux ◽  
Flow Pattern ◽  
Two Phase Flow ◽  
Uniform Heat Flux ◽  
Phase Flow ◽  
Transfer Coefficients ◽  
Two Phase ◽  
Heat Transfer Coefficients ◽  
Uniform Heat

Review of Correlations of Flow Boiling Heat Transfer Coefficients for Nitrogen

2014 ◽  
Author(s):  
Hao Wang ◽  
Xiande Fang
Keyword(s):  
Heat Transfer ◽  
Boiling Heat Transfer ◽  
Two Phase Flow ◽  
Flow Boiling ◽  
Phase Flow ◽  
Transfer Coefficients ◽  
Two Phase ◽  
Heat Transfer Coefficients ◽  
Flow Boiling Heat Transfer ◽  
Comparative Review

As an excellent cryogenic cooling medium, Nitrogen (N2) has been used in a variety of engineering fields, where the determination of N2 two-phase flow boiling heat transfer is required. There were some studies evaluating the correlations of flow boiling heat transfer coefficient for N2. However, either the number of correlations covered or the number of data used was limited. This work presents a comparative review of existing correlations of flow boiling heat transfer coefficients for N2 applications. A database of N2 flow boiling heat transfer containing 1043 experimental data points is compiled to evaluate 45 correlations of two-phase flow boiling heat transfer. The experimental parameters cover the ranges of mass flux from 28.0 to 1684.8 kg/m2s, heat flux from 0.2 to 135.6 kW/m2, vapor quality from 0.002 to 0.994, saturation pressure from 0.1 to 3.16 MPa, and channel inner diameter from 0.351 to 14 mm. The results show that the best correlation has a mean absolute deviation of 31.8% against the whole database, suggesting that more efforts should be made to study N2 flow boiling heat transfer to develop a more accurate correlation.

An Experimental Study of Convective Boiling in a Partially Heated Horizontal Channel With Offset Strip Fins

1988 ◽  
Vol 110 (1) ◽  
pp. 229-236 ◽  
Author(s):  
G. D. Mandrusiak ◽  
V. P. Carey ◽  
X. Xu
Keyword(s):  
Heat Transfer ◽  
Boiling Heat Transfer ◽  
Two Phase Flow ◽  
Horizontal Channel ◽  
Phase Flow ◽  
Transfer Coefficients ◽  
Two Phase ◽  
Convective Boiling ◽  
Heat Transfer Coefficients ◽  
Bottom Heating

Measured local heat transfer data and visually observed two-phase flow behavior are reported for convective boiling of methanol and water in a partially heated horizontal channel with offset strip fins. In this study, a special test section was used that permitted direct visual observation of the two-phase flow while simultaneously measuring the convective boiling heat transfer coefficient at several locations along the channel. One wall of the channel was heated while the opposite and lateral walls were adiabatic. Measured local heat transfer coefficients on the heated portion of the channel wall were obtained for top heating and bottom heating of the horizontal channel. For the conditions examined here, the two-phase flow was in the stratified, wavy, or annular flow regime over almost the entire length of the channel. It was visually observed that virtually no nucleate boiling is present when the flow is in these regimes. A flow regime map is presented, which summarizes the observed two-phase flow characteristics. At the same quality and mass flux levels, the measured heat transfer coefficients for top heating and bottom heating were found to be virtually the same for the conditions examined here. In addition for the same quality and mass flux, the convective boiling heat transfer coefficients for top heating and bottom heating agree well with the results for comparable experiments with the channel oriented vertically. Hence, prior to dryout of the liquid film, the boiling heat transfer performance appears to be insensitive to channel orientation. Observed differences in the dryout conditions for top heating and bottom heating are also discussed.

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