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1.
Akgul Dogan Mercan Hatice Dalkilic Ahmet Selim 《Journal of Thermal Analysis and Calorimetry》2022,147(22):12577-12594
Journal of Thermal Analysis and Calorimetry - In this study, helically coiled tubes are used in a shell, and the effects of tube diameter, coil diameter, Reynolds number, Dean number and flow rate... 相似文献
2.
In the present study, new experimental data are presented for literature on the prediction of film thickness and identification of flow regime during the co-current downward condensation in a vertical smooth copper tube having an inner diameter of 8.1 mm and a length of 500 mm. R134a and water are used as working fluids in the tube side and annular side of a double tube heat exchanger, respectively. Condensation experiments are done at mass fluxes of 300 and 515 kg m?2 s?1. The condensing temperatures are between 40 and 50 °C; heat fluxes are between 12.65 and 66.61 kW m?2. The average experimental heat transfer coefficient of the refrigerant HFC-134a is calculated by applying an energy balance based on the energy transferred from the test section. A mathematical model by Barnea et al. based on the momentum balance of liquid and vapor phases is used to determine the condensation film thickness of R134a. The comparative film thickness values are determined indirectly using relevant measured data together with various void fraction models and correlations reported in the open literature. The effects of heat flux, mass flux, and condensation temperature on the film thickness and condensation heat transfer coefficient are also discussed for the laminar and turbulent flow conditions. There is a good agreement between the film thickness results obtained from the theoretical model and those obtained from six of 35 void fraction models in the high mass flux region of R134a. In spite of their different valid conditions, six well-known flow regime maps from the literature are found to be predictive for the annular flow conditions in the test tube in spite of their different operating conditions. 相似文献
3.
N. Turkan 《Physics of Atomic Nuclei》2010,73(1):64-73
It was pointed out that the level scheme of the transitional nuclei 124,126,128,130,132,134,136Ba also can be studied by both characteristics (IBM-1 and IBM-2) of the interacting boson model and an adequate point of the
model leading to E2 transitions is therefore confirmed. Most of the δ(E2/M1) ratios that are still not known so far are stated and the set of parameters used in these calculations is the best approximation
that has been carried out so far. It has turned out that the interacting boson approximation is fairly reliable for the calculation
of spectra in the entire set of 124,126,128,130,132,134,136Ba isotopes. 相似文献
4.
Residues at the binding sites of the ligand and receptor of several enzyme-inhibitor and antibody-antigen complexes are predicted from the slowest (for the ligand) and fastest (for the receptor) modes of motion by the Gaussian Network Model applied to unbound molecules. 相似文献
5.
S. Laohalertdecha K. Aroonrat A. S. Dalkilic O. Mahian S. Kaewnai S. Wongwises 《Heat and Mass Transfer》2014,50(4):469-482
In this study, experimental and simulation studies of the evaporation heat transfer coefficient and pressure drop of R-134a flowing through corrugated tubes are conducted. The test section is a horizontal counter-flow concentric tube-in-tube heat exchanger 2.0 m in length. A smooth tube and corrugated tubes with inner diameters of 8.7 mm are used as the inner tube. The outer tube is made from a smooth copper tube with an inner diameter of 21.2 mm. The corrugation pitches used in this study are 5.08, 6.35, and 8.46 mm. Similarly, the corrugation depths are 1, 1.25, and 1.5 mm, respectively. The results show that the maximum heat transfer coefficient and pressure drop obtained from the corrugated tube are up to 22 and 19 % higher than those obtained from the smooth tube, respectively. In addition, the average difference of the heat transfer coefficient and pressure drop between the simulation model and experimental data are about 10 and 15 %, respectively. 相似文献
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7.
Turkan Erbay Dalkilic Fatih Tank Kamile Sanli Kula 《Insurance: Mathematics and Economics》2009,45(2):236-241
In this study, we present an approach based on neural networks, as an alternative to the ordinary least squares method, to describe the relation between the dependent and independent variables. It has been suggested to construct a model to describe the relation between dependent and independent variables as an alternative to the ordinary least squares method. A new model, which contains the month and number of payments, is proposed based on real data to determine total claim amounts in insurance as an alternative to the model suggested by Rousseeuw et al. (1984) [Rousseeuw, P., Daniels, B., Leroy, A., 1984. Applying robust regression to insurance. Insurance: Math. Econom. 3, 67–72] in view of an insurer. 相似文献
8.
Adsorption of Basic Yellow 28 from aqueous solutions with clinoptilolite and amberlite 总被引:3,自引:0,他引:3
The objective of this study was to investigate the adsorption of Basic Yellow 28 that is a cationic dye on clinoptilolite and amberlite XAD-4. Both equilibrium and batch rate adsorption in aqueous solutions of the dyestuff were investigated. Adsorption rate data were analysed using the pseudo-first order kinetic model of Lagergren and the pseudo-second order model to determine adsorption rate constants at 20, 30 and 40 degrees C. The adsorption equilibrium data were analysed using various adsorption isotherm models and the results have shown that adsorption behaviour of Basic Yellow 28 by clinoptilolite and amberlite could be described by either Langmuir or Freundlich models. Langmuir adsorption isotherm constants corresponding to adsorption capacity, Q(0), were found to be 59.6, 52.9 and 56.7 mg/g for clinoptilolite at 20, 30 and 40 degrees C, respectively. Lower adsorption capacities for Basic Yellow 28 on amberlite were obtained. The increase of adsorption rate constants with an increase in temperature for BY 28 adsorption on amberlite indicated chemisorption with dissociation and increased availability of sites due to higher penetration of adsorbing molecules into the pores. 相似文献
9.
In this paper, we investigate the transverse linear instability of one-dimensional solitary wave solutions of the coupled system of two-dimensional long-wave–short-wave interaction equations. We show that the one-dimensional solitary waves are linearly unstable to perturbations in the transverse direction if the coefficient of the term associated with transverse effects is negative. This transverse instability condition coincides with the non-existence condition identified in the literature for two-dimensional localized solitary wave solutions of the coupled system. 相似文献
10.
A truncated ULV decomposition (TULVD) of an m×n matrix X of rank k is a decomposition of the form X = ULVT+E, where U and V are left orthogonal matrices, L is a k×k non‐singular lower triangular matrix, and E is an error matrix. Only U,V, L, and ∥E∥F are stored, but E is not stored. We propose algorithms for updating and downdating the TULVD. To construct these modification algorithms, we also use a refinement algorithm based upon that in (SIAM J. Matrix Anal. Appl. 2005; 27 (1):198–211) that reduces ∥E∥F, detects rank degeneracy, corrects it, and sharpens the approximation. Copyright © 2009 John Wiley & Sons, Ltd. 相似文献