Yazar "Kurt, Hueseyin" seçeneğine göre listele
Listeleniyor 1 - 4 / 4
Sayfa Başına Sonuç
Sıralama seçenekleri
Öğe Energy analysis of magnetite nanofluid flowing in newly designed sudden expansion tube retrofitted with dimpled fin(Pergamon-Elsevier Science Ltd, 2022) Guersoy, Emrehan; Pazarlioglu, Hayati Kadir; Dagdeviren, Abdullah; Guerdal, Mehmet; Gedik, Engin; Arslan, Kamil; Kurt, HueseyinSudden expansion geometry plays an important role in the design of many engineering applications such as heat exchangers to avoid thermal stress on welded joints. While the heat transfer in these geometries is maximized at the reattachment points, it decreases to a minimum in the recirculation regions created by the fluid. To prevent this situation and improve the performance of the expansion tubes, nanofluid, and expanded surfaces can be used. For this purpose, forced convection of magnetite nanofluid flow in various expansion ratios has been investigated numerically in this study. Analyses have been performed on Reynolds ( Re ) numbers ranging from 100 to 2000, constant and uniform heat flux at 600 W/m(2), and volume concentrations (1.0 <=phi <= 2.0 vol.%). The result showed that while the Nu number increases with increasing Re number , the most efficient case is Dimpled Tube ( DT ) 9, and the highest value of performance evaluation criteria (PEC) has been obtained at phi= 2.0 vol.%. Compared with the water, the highest Nu number value has been obtained as 3.34% increased at Re = 20 0 0 and phi= 2.0 vol.%. When compared to the DT9 and Smooth Tube ( ST ) 1 where water was used as the working fluid at Re = 20 0 0 and phi= 2.0 vol.%, the PEC value increased by 8.66% and 110.31%, respectively. In addition, the bottom wall of the DT9 case performs higher convective heat transfer rate than the top wall.(c) 2022 Elsevier Ltd. All rights reserved.Öğe Performance analysis of open cycle gas turbines(John Wiley & Sons Ltd, 2009) Kurt, Hueseyin; Recebli, Ziyaddin; Gedik, EnginIn this study, the performance of ideal open cycle gas turbine system was examined based on its thermodynamic analysis. The effects of some parameters, such as compressor inlet temperature (CIT), pressure ratio (PR) and the turbine inlet temperature (TIT), on the performance parameters of open cycle gas turbine were discussed. The turbine net power output, the thermal efficiency and the fuel consumption of the turbine were taken as the performance parameters. The values of these parameters were calculated using some basic cycle equations and variables values of thermodynamic properties. Other variables such as lower heating value, combustion efficiency and isentropic efficiencies of compressor and turbine were assumed to be constant. The result showed that the net power output and the thermal efficiency increased by a decrease in the CIT and increase in the TIT and PR values. If it is aimed to have a high net power output and the thermal efficiency for the turbine, the CIT should be chosen as low as possible and the TIT should be chosen as high as possible. Copyright (C) 2008 John Wiley & Sons, Ltd.Öğe Prediction of thermal conductivity of ethylene glycol-water solutions by using artificial neural networks(Elsevier Sci Ltd, 2009) Kurt, Hueseyin; Kayfeci, MuhammetThe objective of this study is to develop an artificial neural network (ANN) model to predict the thermal conductivity of ethylene glycol-water solutions based on experimentally measured variables. The thermal conductivity of solutions at different concentrations and various temperatures was measured using the cylindrical cell method that physical properties of the solution are being determined fills the annular space between two concentric cylinders. During the experiment, heat flows in the radial direction outwards through the test liquid filled in the annual gap to cooling water. In the steady state, conduction inside the cell was described by the Fourier equation in cylindrical coordinates, with boundary conditions corresponding to heat transfer between the solution and cooling water. The performance of ANN was evaluated by a regression analysis between the predicted and the experimental values. The ANN predictions yield R 2 in the range of 0.9999 and MAPE in the range of 0.7984% for the test data set. The regression analysis indicated that the ANN model can successfully be used for the prediction of the thermal conductivity of ethylene glycol-water solutions with a high degree of accuracy. (C) 2008 Elsevier Ltd. All rights reserved.Öğe Thermal performance parameters estimation of hot box type solar cooker by using artificial neural network(Elsevier France-Editions Scientifiques Medicales Elsevier, 2008) Kurt, Hueseyin; Atik, Kemal; Ozkaymak, Mehmet; Recebli, ZiyaddinWork to date has shown that Artificial Neural Network (ANN) has not been used for predicting thermal performance parameters of a solar cooker. The objective of this study is to predict thermal performance parameters such as absorber plate, enclosure air and pot water temperatures of the experimentally investigated box type solar cooker by using the ANN. Data set is obtained from the box type solar cooker which was tested under various experimental conditions. A feed-forward neural network based on back propagation algorithm was developed to predict the thermal performance of solar cooker with and without reflector. Mathematical formulations derived from the ANN model are presented for each predicting temperatures. The experimental data set consists of 126 values. These were divided into two groups, of which the 96 values were used for training/learning of the network and the rest of the data (30 values) for testing/validation of the network performance. The performance of the ANN predictions was evaluated by comparing the prediction results with the experimental results. The results showed a good regression analysis with the correlation coefficients in the range of 0.9950-0.9987 and mean relative errors (MREs) in the range of 3.92516-7.040% for the test data set. The regression coefficients indicated that the ANN model can successfully be used for the prediction of the thermal performance parameters of a box type solar cooker with a high degree of accuracy. (c) 2007 Elsevier Masson SAS. All rights reserved.