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Sunil Chamoli - One of the best experts on this subject based on the ideXlab platform.
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ann and rsm approach for modeling and optimization of designing parameters for a v down perforated baffle roughened Rectangular Channel
alexandria engineering journal, 2015Co-Authors: Sunil ChamoliAbstract:Abstract The turbulence promoters are widely used to enhance the performance of Rectangular Channel which were used for turbine blade passage cooling. In the present study, the influence of design parameters of the V down perforated baffle roughened Rectangular Channel on the heat transfer and friction factor was investigated using RSM and ANN. The quadratic model generated by RSM is used to predict the performance parameters, i.e. Nusselt number and friction factor with reasonably good accuracy. The optimum values of the design parameters of the V down perforated baffle roughened Rectangular Channel are relative roughness pitch of 2.6, relative roughness height of 0.33, open area ratio of 18% and Reynolds number of 18,500, in the desirable range of the order of 0.95. The training of the experimental data is carried out using 4-10-2 neural network and the predicted values are compared with the experimental values and found deviation in the range of ±10% among predicted and experimental values. The comparison of predicted values by RSM and ANN with the experimental values was carried out for each run of experiment and it was observed that the RSM predicted values are in accord with the experimental values in the uncertainty range of ±5%.
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hybrid fahp fuzzy analytical hierarchy process ftopsis fuzzy technique for order preference by similarity of an ideal solution approach for performance evaluation of the v down perforated baffle roughened Rectangular Channel
Energy, 2015Co-Authors: Sunil ChamoliAbstract:Abstract In the present study a methodology has been proposed to evaluate the performance of the V down perforated baffle roughened Rectangular Channel using hybrid FAHP-FOPSIS approach. The hybrid FAHP (fuzzy analytical hierarchy process) and FTOPSIS (fuzzy technique for order preference by similarity of an ideal solution) approach, taking into account PDAs (performance defining attributes), such as Nusselt number ratio, friction factor ratio, thermohydraulic performance parameter and effective efficiency, was used for the performance prediction of the V down perforated baffle roughened Rectangular Channel. The weight of different PDAs was evaluated by FAHP; Nu rat (0.060, 0.093, 0.138), f rat (0.045, 0.066, 0.105), e (0.170, 0.244, 0.352) and η eff (0.431, 0.597, 0.821), respectively. FTOPSIS was employed to determine the optimum ranking of the V down perforated baffle roughened Rectangular Channel and the values obtained as; C6 > C5 > C8 > C7 > C9 > C10 > C2>C11 > C12 > C1 > C3 > C13 > C14 > C4 > C15 > C16. The test plate (alternative) with an open area ratio (β) of 24%, relative roughness pitch (P/e) of 2 and relative roughness height (e/H) of 0.4, exhibits the optimal formulation.
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a taguchi approach for optimization of flow and geometrical parameters in a Rectangular Channel roughened with v down perforated baffles
Case Studies in Thermal Engineering, 2015Co-Authors: Sunil ChamoliAbstract:Abstract This study presents the optimum design parameters of the Rectangular Channel with V down perforated baffle turbulators using a Taguchi experimental design method. The experimental investigation for the established Rectangular Channel involves V down perforated baffles attached to the one of the broad wall of the Channel having various roughness parameters. The effects of the four design parameters such as Reynolds number, open area ratio, relative roughness height and relative roughness pitch are investigated. In the Taguchi experimental design method, Nusselt number and friction are considered as performance parameter. An L 16 (4 4 ) orthogonal array is chosen as an experimental plan for the design parameters. The analysis of Taguchi method conducted with the goal of optimization process for minimum friction factor (minimum pressure drop) and maximum Nusselt number (maximum heat transfer) for the designed V down perforated baffle roughened Rectangular Channel. The optimum configurations of control factors for Nusselt number and friction factor are A 2 B 2 C 1 D 4 and A 4 B 1 C 4 D 3 , respectively. Experimental results validated the suitability of the proposed approach.
Sichao Tan - One of the best experts on this subject based on the ideXlab platform.
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experimental investigation on flow instability of forced circulation in a mini Rectangular Channel under rolling motion
International Journal of Heat and Mass Transfer, 2016Co-Authors: Sichao Tan, Hongsheng Yuan, Chong Chen, Xianbing ChenAbstract:Abstract An experimental study was performed in a mini-Rectangular Channel under rolling condition to investigate the flow instability of forced circulation. In order to analyze the influence of rolling motion on two-phase flow instability, experiments under both static condition and rolling condition were conducted using the same thermodynamic parameters, such as flow rate, system pressure and inlet fluid temperature. During the experiments, typical pressure drop oscillation (PDO) was observed in static condition, while abundant experimental phenomena including single-phase flow fluctuation, trough-type flow oscillation, coupled flow oscillation and two-phase flow fluctuation were found in rolling condition. Single-phase flow fluctuation, which fluctuates in sinusoidal wave, is directly induced by rolling motion, while two-phase flow fluctuation is supposed to be in annular flow regime which is accompanied with fluctuation caused by rolling motion. Trough-type flow oscillation is confirmed as the boiling incipience according to the pressure drop and heat transfer characteristics. As intermittent boiling occurs at the section close to the outlet of the test Channel, during trough-type flow oscillation, two wave peaks in one rolling period are found in the pressure drop fluctuation of the outlet section of the Channel. The method of Fast Fourier Transform (FFT) is used to analyze the coupled flow oscillation, and two frequencies, including the rolling frequency and PDO frequency, are found in the amplitude spectrum. Thus, the coupled flow oscillation is supposed to be superposition of trough-type flow oscillation and PDO. Besides, the coupling mechanisms of the coupled flow oscillation are discussed and the evolution characteristics of flow instabilities are presented.
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flow fluctuations and flow friction characteristics of vertical narrow Rectangular Channel under rolling motion conditions
Experimental Thermal and Fluid Science, 2013Co-Authors: Sichao Tan, Zhanwei Wang, Chang Wang, Shu LanAbstract:Abstract Experimental investigations on flow fluctuations and friction characteristics of a vertical narrow Rectangular Channel under rolling motion condition are carried out. This experiment is designed to acquire the flow rate fluctuation boundary of forced single-phase flow in rolling motion and to get an insight into the flow friction characteristics under large flow rate fluctuation amplitudes. The results show that the amplitude of flow rate fluctuations increase with increasing rolling amplitude and the valve opening while decrease with the increase of the rolling period and driving head. The time average friction coefficient can be obtained by two kinds of methods, one calculated by integrating the instantaneous friction coefficient in one period is related to the viscous dissipation and the other acquired by the Darcy equation which employs time average pressure drop and velocity represents time average frictional pressure drop. A correlation for the instantaneous friction coefficient is developed, which could also apply to steady condition when the rolling frequency or rolling amplitude approaches zero.
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forced convection heat transfer and flow characteristics in laminar to turbulent transition region in Rectangular Channel
Experimental Thermal and Fluid Science, 2013Co-Authors: Chang Wang, Sichao Tan, Puzhen Gao, Zhanwei WangAbstract:Abstract Experimental investigations are performed on the forced convection heat transfer and friction characteristics in laminar to turbulent transition region in a vertical heated Rectangular Channel. The experiment is designed for analyzing the effect of Prandtl number on the heat transfer and friction characteristics in the transition region. Seven groups of experiments are carried out within the range of Reynolds number from 1000 to 2 × 104, and the Prandtl number in each group is 2.10, 2.34, 2.51, 2.69, 2.93, 3.18, and 3.45, respectively. The results show that the lower and the upper critical Reynolds number of transition region increase with the decrease of Prandtl number. However, the friction factors increase with increasing Prandtl number for a fixed Reynolds number in the transition region. In addition, the comparisons between present experimental data and classical correlations indicate that none of the existing correlations could be extended to predict the present friction and heat transfer characteristics in the transition region of the heated Channel. Based on the experimental data, the empirical correlations for the calculation of friction factor and heat transfer coefficient in the Rectangular Channel in the flow transition region of forced circulation have been developed.
F C Walsh - One of the best experts on this subject based on the ideXlab platform.
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characterisation of platinum electrodeposits on a titanium micromesh stack in a Rectangular Channel flow cell
Electrochimica Acta, 2017Co-Authors: Luis F Arenas, Carlos Ponce De Leon, Richard P Boardman, F C WalshAbstract:Abstract Platinised titanium mesh is a common electrode material in industrial electrolytic cells and Ce-based redox flow batteries. In this work, the electrodeposition of platinum on a stack of titanium micromeshes is performed from a flowing alkaline solution in a Rectangular Channel, divided flow cell. The morphology and distribution of the resulting platinum deposits are studied by SEM, EDS mapping and X-ray computed tomography. The active surface area of the electrode was assessed from the charge transfer current for the reduction of Ce(IV) ions and compared to that of planar and expanded metal mesh electrodes. The surface area was estimated by hydrogen electrosorption relative to that at a planar Pt/Ti electrode. As expected from the potential drop within the electrode Channel, the individual micromesh near the cell separator showed a higher platinum content. Pt/Ti micromesh offers an extended surface area and enhanced mass transport compared to planar electrodes and conventional expanded metal mesh anodes. The applications for these and alternative electrode structures are discussed.
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editors choice electrodeposition of platinum on titanium felt in a Rectangular Channel flow cell
Journal of The Electrochemical Society, 2017Co-Authors: Luis F Arenas, Carlos Ponce De Leon, Richard P Boardman, F C WalshAbstract:Highly porous platinised titanium substrates are attractive electrode materials for industrial electrochemical processing and electrochemical energy storage. The electrodeposition of platinum on titanium felt was carried out in a divided, Rectangular Channel flow cell from an alkaline bath without additives. The morphology and spatial distribution of the platinum deposits in the porous material were analysed using SEM and EDS microscopy in addition to X-ray computed tomography (CT). The electroplated surface area was estimated from the charge transfer current ratio for Ce(IV) reduction and related to a theoretical electrosorbed hydrogen monolayer surface area. The platinised titanium felt showed a significant enhancement of active surface area in comparison to conventional electrode materials. Although platinum was present throughout the porous electrode, CT revealed heterogeneous deposits accumulating in regions near the membrane (during electrodeposition), as a result of the potential distribution in the felt material and flowing electrolyte. Uniform platinum coatings are possible on thin titanium felt under 200 µm thick, by either potentiostatic or galvanostatic electrodeposition.Data for the paper Arenas Martinez, Luis, Ponce De Leon Albarran, Carlos, Boardman, Richard and Walsh, Frank (2016) Electrodeposition of platinum on titanium felt in a Rectangular Channel flow cell. Journal of The Electrochemical Society, 164, (2), D1-D10. (doi:10.1149/2.0651702jes)
Zhanwei Wang - One of the best experts on this subject based on the ideXlab platform.
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flow fluctuations and flow friction characteristics of vertical narrow Rectangular Channel under rolling motion conditions
Experimental Thermal and Fluid Science, 2013Co-Authors: Sichao Tan, Zhanwei Wang, Chang Wang, Shu LanAbstract:Abstract Experimental investigations on flow fluctuations and friction characteristics of a vertical narrow Rectangular Channel under rolling motion condition are carried out. This experiment is designed to acquire the flow rate fluctuation boundary of forced single-phase flow in rolling motion and to get an insight into the flow friction characteristics under large flow rate fluctuation amplitudes. The results show that the amplitude of flow rate fluctuations increase with increasing rolling amplitude and the valve opening while decrease with the increase of the rolling period and driving head. The time average friction coefficient can be obtained by two kinds of methods, one calculated by integrating the instantaneous friction coefficient in one period is related to the viscous dissipation and the other acquired by the Darcy equation which employs time average pressure drop and velocity represents time average frictional pressure drop. A correlation for the instantaneous friction coefficient is developed, which could also apply to steady condition when the rolling frequency or rolling amplitude approaches zero.
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forced convection heat transfer and flow characteristics in laminar to turbulent transition region in Rectangular Channel
Experimental Thermal and Fluid Science, 2013Co-Authors: Chang Wang, Sichao Tan, Puzhen Gao, Zhanwei WangAbstract:Abstract Experimental investigations are performed on the forced convection heat transfer and friction characteristics in laminar to turbulent transition region in a vertical heated Rectangular Channel. The experiment is designed for analyzing the effect of Prandtl number on the heat transfer and friction characteristics in the transition region. Seven groups of experiments are carried out within the range of Reynolds number from 1000 to 2 × 104, and the Prandtl number in each group is 2.10, 2.34, 2.51, 2.69, 2.93, 3.18, and 3.45, respectively. The results show that the lower and the upper critical Reynolds number of transition region increase with the decrease of Prandtl number. However, the friction factors increase with increasing Prandtl number for a fixed Reynolds number in the transition region. In addition, the comparisons between present experimental data and classical correlations indicate that none of the existing correlations could be extended to predict the present friction and heat transfer characteristics in the transition region of the heated Channel. Based on the experimental data, the empirical correlations for the calculation of friction factor and heat transfer coefficient in the Rectangular Channel in the flow transition region of forced circulation have been developed.
Shu Lan - One of the best experts on this subject based on the ideXlab platform.
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flow fluctuations and flow friction characteristics of vertical narrow Rectangular Channel under rolling motion conditions
Experimental Thermal and Fluid Science, 2013Co-Authors: Sichao Tan, Zhanwei Wang, Chang Wang, Shu LanAbstract:Abstract Experimental investigations on flow fluctuations and friction characteristics of a vertical narrow Rectangular Channel under rolling motion condition are carried out. This experiment is designed to acquire the flow rate fluctuation boundary of forced single-phase flow in rolling motion and to get an insight into the flow friction characteristics under large flow rate fluctuation amplitudes. The results show that the amplitude of flow rate fluctuations increase with increasing rolling amplitude and the valve opening while decrease with the increase of the rolling period and driving head. The time average friction coefficient can be obtained by two kinds of methods, one calculated by integrating the instantaneous friction coefficient in one period is related to the viscous dissipation and the other acquired by the Darcy equation which employs time average pressure drop and velocity represents time average frictional pressure drop. A correlation for the instantaneous friction coefficient is developed, which could also apply to steady condition when the rolling frequency or rolling amplitude approaches zero.