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Xiang Ling - One of the best experts on this subject based on the ideXlab platform.
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Numerical study and experimental verification of transverse direction type serrated fins and field synergy principle analysis
Applied Thermal Engineering, 2013Co-Authors: Hao Peng, Xiang LingAbstract:The heat transfer and pressure drop characteristics of transverse direction (TD) type aluminum serrated fins in compact heat exchanger were studied experimentally and numerically in this paper. Firstly, taken lubricant as working fluid and water as coolant, performance tests were carried out for different flow rates in oil side. Variation in the Colburn Factor j and the friction Factor f relative to Re were examined. Next to that, the effects of structural parameters on thermal characteristics of TD type serrated fins were analyzed numerically. Through comparison of experimental and simulated results, the tendencies agree well. Finally, the heat transfer enhancement mechanism for TD type serrated fins was discussed by field synergy principle (FSP) theory. It is found that vortexes generated near the TD fin region enhanced the turbulence intensity to reduce the thickness of boundary and improve the synergy between the velocity and temperature gradient.
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neural networks analysis of thermal characteristics on plate fin heat exchangers with limited experimental data
Applied Thermal Engineering, 2009Co-Authors: Hao Peng, Xiang LingAbstract:Abstract In this paper, an application of artificial neural networks (ANNs) was presented to predict the pressure drop and heat transfer characteristics in the plate-fin heat exchangers (PFHEs). First, the thermal performances of five different PFHEs were evaluated experimentally. The Colburn Factor j and friction Factor f to different type fins were obtained under various experimental conditions. Then, a feed-forward neural network based on back propagation algorithm was developed to model the thermal performance of the PFHEs. The ANNs was trained using the experimental data to predict j and f Factors in PFHEs. Different network configurations were also examined for searching a better network for prediction. The predicted values were found to be in good agreement with the actual values from the experiments with mean squared errors (MSE) less than 1.5% for j Factor and 1% for f Factor, respectively. This demonstrated that the neural network presented can help the engineers and manufacturers predict the thermal characteristics of new type fins in PFHEs under various operating conditions.
C Ranganayakulu - One of the best experts on this subject based on the ideXlab platform.
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Colburn ‘j’ Factor and Fanning Friction Factor ‘f’ Correlations of Triangular Plain Fin Surface of a Compact Heat Exchanger Using CFD
Applied Mechanics and Materials, 2015Co-Authors: G Ranganath, C RanganayakuluAbstract:This paper presents the heat transfer and friction coefficient correlations for triangular plain fin surfaces of plate fin compact heat exchanger. It will be prohibitively expensive and time consuming to fabricate heat exchanger cores and conduct experiments over reasonable ranges of all the geometric variables. In contrast, it is relatively easy and cost effective to carry out a parametric study through numerical simulation and derive acceptable correlations for use in industry. A numerical model has been developed for the triangular plain fin of plate fin heat exchanger. The CFD analysis is carried out using FLUENT 12.1, Colburn Factor j and fanning friction Factor f are calculated for different Reynolds numbers. These values are compared with the available literature data of j and f Factors. The correlations have been expressed in terms of two separate equations over the low and high Re regions along with dimensionless geometric parameters.
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Colburn j Factor and fanning friction Factor f correlations of triangular plain fin surface of a compact heat exchanger using cfd
Applied Mechanics and Materials, 2015Co-Authors: Ramisetty Bala Sundar Rao, G Ranganath, C RanganayakuluAbstract:This paper presents the heat transfer and friction coefficient correlations for triangular plain fin surfaces of plate fin compact heat exchanger. It will be prohibitively expensive and time consuming to fabricate heat exchanger cores and conduct experiments over reasonable ranges of all the geometric variables. In contrast, it is relatively easy and cost effective to carry out a parametric study through numerical simulation and derive acceptable correlations for use in industry. A numerical model has been developed for the triangular plain fin of plate fin heat exchanger. The CFD analysis is carried out using FLUENT 12.1, Colburn Factor j and fanning friction Factor f are calculated for different Reynolds numbers. These values are compared with the available literature data of j and f Factors. The correlations have been expressed in terms of two separate equations over the low and high Re regions along with dimensionless geometric parameters.
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Development of Colburn ‘j’ Factor and fanning friction Factor ‘f’ correlations for compact heat exchanger plain fins by using CFD
Heat and Mass Transfer, 2013Co-Authors: R. Bala Sundar Rao, G Ranganath, C RanganayakuluAbstract:A numerical model has been developed for plain fin of plate fin heat exchanger. Plain fin performance has been analyzed with the help of CFD by changing the various parameters of the fin, Colburn ‘ j ’ and fanning friction ‘ f ’ Factors are calculated. These values compared with the standard values. The correlations have been developed between Reynolds number Re , fin height h, fin thickness t, fin spacing s, Colburn Factor ‘ j ’ and friction Factor ‘ f ’.
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development of Colburn j Factor and fanning friction Factor f correlations for compact heat exchanger plain fins by using cfd
Heat and Mass Transfer, 2013Co-Authors: G Ranganath, C RanganayakuluAbstract:A numerical model has been developed for plain fin of plate fin heat exchanger. Plain fin performance has been analyzed with the help of CFD by changing the various parameters of the fin, Colburn ‘j’ and fanning friction ‘f’ Factors are calculated. These values compared with the standard values. The correlations have been developed between Reynolds number Re, fin height h, fin thickness t, fin spacing s, Colburn Factor ‘j’ and friction Factor ‘f’.
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numerical study of flow patterns of compact plate fin heat exchangers and generation of design data for offset and wavy fins
International Journal of Heat and Mass Transfer, 2009Co-Authors: Sheik L Ismail, C Ranganayakulu, Ramesh K ShahAbstract:Abstract Thermo-hydraulic design of compact heat exchangers (CHEs) is strongly dependent upon the predicted/measured dimensionless performance (Colburn Factor j and Fanning friction Factor f vs. Reynolds number Re) of heat transfer surfaces. Also, air (gas) flow maldistribution in the headers, caused by the orientation of inlet and outlet nozzles in the heat exchanger, affects the exchanger performance. Three typical compact plate-fin heat exchangers have been analyzed using Fluent software for quantification of flow maldistribution effects with ideal and real cases. The headers have modified by providing suitable baffle plates for improvement in flow distribution. Three offset strip fin and 16 wavy fin geometries used in the compact plate-fin heat exchangers have also been analyzed numerically. The j and f vs. Re design data are generated using CFD analysis only for turbulent flow region. For the validation of the numerical analysis conducted in the present study, a rectangular fin geometry having same dimensions as that of the wavy fin has been analyzed. The results of the wavy fin have been compared with the analytical results of a rectangular fin and found good agreement. Similarly, the numerical results of offset strip fin are compared with the correlations available in the open literature and found good agreement with most of the earlier findings.
Hao Peng - One of the best experts on this subject based on the ideXlab platform.
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Numerical study and experimental verification of transverse direction type serrated fins and field synergy principle analysis
Applied Thermal Engineering, 2013Co-Authors: Hao Peng, Xiang LingAbstract:The heat transfer and pressure drop characteristics of transverse direction (TD) type aluminum serrated fins in compact heat exchanger were studied experimentally and numerically in this paper. Firstly, taken lubricant as working fluid and water as coolant, performance tests were carried out for different flow rates in oil side. Variation in the Colburn Factor j and the friction Factor f relative to Re were examined. Next to that, the effects of structural parameters on thermal characteristics of TD type serrated fins were analyzed numerically. Through comparison of experimental and simulated results, the tendencies agree well. Finally, the heat transfer enhancement mechanism for TD type serrated fins was discussed by field synergy principle (FSP) theory. It is found that vortexes generated near the TD fin region enhanced the turbulence intensity to reduce the thickness of boundary and improve the synergy between the velocity and temperature gradient.
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neural networks analysis of thermal characteristics on plate fin heat exchangers with limited experimental data
Applied Thermal Engineering, 2009Co-Authors: Hao Peng, Xiang LingAbstract:Abstract In this paper, an application of artificial neural networks (ANNs) was presented to predict the pressure drop and heat transfer characteristics in the plate-fin heat exchangers (PFHEs). First, the thermal performances of five different PFHEs were evaluated experimentally. The Colburn Factor j and friction Factor f to different type fins were obtained under various experimental conditions. Then, a feed-forward neural network based on back propagation algorithm was developed to model the thermal performance of the PFHEs. The ANNs was trained using the experimental data to predict j and f Factors in PFHEs. Different network configurations were also examined for searching a better network for prediction. The predicted values were found to be in good agreement with the actual values from the experiments with mean squared errors (MSE) less than 1.5% for j Factor and 1% for f Factor, respectively. This demonstrated that the neural network presented can help the engineers and manufacturers predict the thermal characteristics of new type fins in PFHEs under various operating conditions.
J.l. Bhagoria - One of the best experts on this subject based on the ideXlab platform.
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Exergy evaluation of packed bed solar air heater
Renewable and Sustainable Energy Reviews, 2012Co-Authors: Mukesh Kumar Lalji, R.m. Sarviya, J.l. BhagoriaAbstract:Abstract In view of above present investigation is planned with the following. The present investigation has been carried out with the following objectives: (1) To study performance of packed bed solar air heater for high porosity range and for different shapes of matrices. (2) Development of correlations for heat transfer coefficient and friction Factor for packed bed solar air heater and its comparison with conventional design. (3) Exergy analysis of packed bed solar air heater. The present study involved outdoor experimental work for generation of heat transfer and friction data for flow in a packed bed solar air heater at different mass flow rates of air for various porosities and shapes of matrices. Data is also collected for conventional smooth duct under similar operating conditions for ensuring accuracy of experimental data. Six matrices had been tested for seven values of flow rates corresponding to flow Reynolds number of about 1000–4700 and data is collected under steady state condition. Ranges of parameters covered in this experimental investigation are as follows: Reynolds number, Re=1000–4700 Porosity, P=0.9614–0.9984 Number of layers, n=3–6 It is found that in the entire range of Reynolds number, Colburn Factor decreases with an increase of packing Reynolds number and volumetric heat transfer increased monotonically with a decrease in porosity. Also from the various matrices studied hexagonal shaped matrix performed lowest of all other matrices. Square shaped matrix performed best amongst the matrices studied. Following correlations have been developed for Colburn Factor and friction Factor in terms of porosity and operating parameters: J h = 0 . 1765 [ ( 1 / nP ) 0.6156 ) ( p t / d w ) 0.1229 ] 0.6651 R e p − 0.4767 f p = 2.0291 [ ( 1 / nP ) 0.3521 ) ( p t / d w ) 0.0686 ] 0.6759 R e p − 0.3897 .
Yasar Islamoglu - One of the best experts on this subject based on the ideXlab platform.
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Computational investigation of the velocity and temperature fields in corrugated heat exchanger channels using RANS based turbulence models with experimental validation
Progress in Computational Fluid Dynamics An International Journal, 2018Co-Authors: Erman Aslan, Imdat Taymaz, Yasar Islamoglu, Mardiros Engin, Ilkay Colpan, Gokhan Karabas, Guven OzcelikAbstract:The characteristics of convective heat transfer and friction Factor for periodic corrugated channels are investigated numerically. In the numerical study, the finite volume method (FVM) is used. Three different Reynolds averaged numerical simulation (RANS) based turbulent models, namely the k-ω, the shear stress transport (SST) model and the transition SST model are employed and compared with each other. Experimental results obtained from a previous study are used for the assessment of the numerical results. Investigations are performed for air flowing through corrugated channels with an inclination angle of 30°. The Reynolds number is varied within the range 2,000 to 11,000, while keeping the Prandtl number constant at 0.70. Variations of the Nusselt number, Colburn Factor, friction Factor and goodness Factor with the Reynolds number are studied. Effects of the corrugation geometry and channel height are discussed. The overall performances of the considered turbulence model are observed to be quite similar. The SST model is observed to show a slightly better overall performance.
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Finite volume simulation for convective heat transfer in wavy channels
Heat and Mass Transfer, 2016Co-Authors: Erman Aslan, Imdat Taymaz, Yasar IslamogluAbstract:The convective heat transfer characteristics for a periodic wavy channel have been investigated experimentally and numerically. Finite volume method was used in numerical study. Experiment results are used for validation the numerical results. Studies were conducted for air flow conditions where contact angle is 30°, and uniform heat flux 616 W/m^2 is applied as the thermal boundary conditions. Reynolds number ( Re ) is varied from 2000 to 11,000 and Prandtl number ( Pr ) is taken 0.7. Nusselt number ( Nu ), Colburn Factor ( j ), friction Factor ( f ) and goodness Factor ( j / f ) against Reynolds number have been studied. The effects of the wave geometry and minimum channel height have been discussed. Thus, the best performance of flow and heat transfer characterization was determined through wavy channels. Additionally, it was determined that the computed values of convective heat transfer coefficients are in good correlation with experimental results for the converging diverging channel. Therefore, numerical results can be used for these channel geometries instead of experimental results.
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Experimental study of forced convective heat transfer in a different arranged corrugated channel
International Communications in Heat and Mass Transfer, 2013Co-Authors: H. Pehlivan, Imdat Taymaz, Yasar IslamogluAbstract:Abstract In this study, heat transfer rate for sinusoidal corrugated channel has been experimentally investigated. Three different type sharp corrugation peak fins and a plain surface were used in the experiment. Results were carried out for constant heat flux of 616 W/m 2 , varied Reynolds number Re 1500 to 8000 for the corrugation angle (27, 50 and 22/60°) and channel height of 5 and 10 mm. Nusselt number (Nu), convection heat transfer coefficient (h), Colburn Factor (j) and enhancement ratio (E) against Reynolds number (Re) have been studied. The effects of the wavy geometry and channel height have been discussed. The increase of corrugated angle gave rise to a heat transfer rate.
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Optimal design of a converging diverging channel for convective heat transfer enhancement in fully developed turbulent air flow
International Journal of Thermal Sciences, 1Co-Authors: Zekeriya Parlak, Nezaket Parlak, Yasar IslamogluAbstract:Abstract The optimization operation has been performed with ANSYS Response Surface Optimization Tool to find optimum channel geometry for converging-diverging channels. Steady state, three dimensional, turbulence, viscous, compressible, single-phase Newtonian flow is assumed through the channel with rectangular cross section. In the study, output parameters have been selected as Colburn Factor and Darcy friction Factor. Effects of channel width, wavelength and amplitude of converging-diverging channel on output parameters have been examined and non-dimensionless results have been obtained for optimal geometries for three different Reynolds numbers (Re = 4400, 5600 and 6700). To analyze the thermal-hydraulic performance of the optimum wavy channel, thermal performance Factors (TPF) are calculated. Results showed that optimized channel is more efficient than straight channel, TPF values for optimized channel were ranged from 1.7 to 1.4 over the range of Re studied.