Numerical Simulation of 3—D Temperature Distribution of the Flame Tube of the Combustion Chamber with Air Film COoling

ＮｕｍｅｒｉｃａｌＳｉｍｕｌａｔｉｏｎｏｆ３－ＤＴｅｍｐｅｒａｔｕｒｅＤｉｓｔｒｉｂｕｔｉｏｎｏｆｔｈｅＦｌａｍｅＴｕｂｅｏｆｔｈｅＣｏｍｂｕｓｔｉｏｎＣｈａｍｂｅｒｗｉｔｈＡｉｒＦｉｌｍＣｏｏｌｉｎｇＮｕｍｅｒｉｃａｌＳｉｍｕｌａｔｉｏｎｏｆ３－Ｄ...     

Comparison of a Reaction Front Model and a Finite Difference Model for the Simulation of Solid Absorption Process

ＣｏｍｐａｒｉｓｏｎｏｆａＲｅａｃｔｉｏｎＦｒｏｎｔＭｏｄｅｌａｎｄａＦｉｎｉｔｅＤｉｆｆｅｒｅｎｃｅＭｏｄｅｌｆｏｒｔｈｅＳｉｍｕｌａｔｉｏｎｏｆＳｏｌｉｄＡｂｓｏｒｐｔｉｏｎＰｒｏｃｅｓｓ￥ＺｉｋａｎｇＷｕ；ＡｒｎｅＪａｋｏｂｓｅｎ；Ｘｉｕｇａｎ...     

Forced Convective Condensation of Nonazeotropic Refrigerant Mixtures in Horizontal Annulus with Petal Shaped Fin Tubes

ＦｏｒｃｅｄＣｏｎｖｅｃｔｉｖｅＣｏｎｄｅｎｓａｔｉｏｎｏｆＮｏｎａｚｅｏｔｒｏｐｉｃＲｅｆｒｉｇｅｒａｎｔＭｉｘｔｕｒｅｓｉｎＨｏｒｉｚｏｎｔａｌＡｎｎｕｌｕｓｗｉｔｈＰｅｔａｌＳｈａｐｅｄＦｉｎＴｕｂｅｓＷａｎｇＳｈｉｐｉｎｇ；ＺｈｏｕＸｉｎｑｉ...     

Analysis of Entropy Generation of Combined Heat and Mass Transfer in Internal and External Flows with the Assumption of Local Thermodynamic Equilibrium

ＡｎａｌｙｓｉｓｏｆＥｎｔｒｏｐｙＧｅｎｅｒａｔｉｏｎｏｆＣｏｍｂｉｎｅｄＨｅａｔａｎｄＭａｓｓＴｒａｎｓｆｅｒｉｎＩｎｔｅｒｎａｌａｎｄＥｘｔｅｒｎａｌＦｌｏｗｓｗｉｔｈｔｈｅＡｓｓｕｍｐｔｉｏｎｏｆＬｏｃａｌＴｈｅｒｍｏｄｙｎａｍｉｃＥｑｕｉｌｉ...     

JOURNAL OF THERMAL SCIENCE（JTS） International Journal of Thermal and Fluid Sciences

ＪＯＵＲＮＡＬＯＦＴＨＥＲＭＡＬＳＣＩＥＮＣＥ（ＪＴＳ）ＩｎｔｅｒｎａｔｉｏｎａｌＪｏｕｒｎａｌｏｆＴｈｅｒｍａｌａｎｄＦｌｕｉｄＳｃｉｅｎｃｅｓ￥ＥｄｉｔｏｒｉａｌＡｄｖｉｓｏｒｙＢｏａｒｄＪＯＵＲＮＡＬＯＦＴＨＥＲＭＡＬＳＣＩＥＮＣＥ（ＪＴＳ）Ｉ...     

A Novel Variational Formulation of Inverse Problem of Heat Conduction with Free Boundary on an Image

ＡＮｏｖｅｌＶａｒｉａｔｉｏｎａｌＦｏｒｍｕｌａｔｉｏｎｏｆＩｎｖｅｒｓｅＰｒｏｂｌｅｍｏｆＨｅａｔＣｏｎｄｕｃｔｉｏｎｗｉｔｈＦｒｅｅＢｏｕｎｄａｒｙｏｎａｎＩｍａｇｅＰｌａｎｅＧａｏ－ＬｉａｎＬｉｕ（ＳｈａｎｇｈａｉＩｎｓｔｉｔｕｔｅｏｆＭｅｃｈ...     

Numerical Solution of Flow Field Diagnosis Problem in Multistage Axial Compressors

Ｎｕｍｅｒｉｃａｌ　Ｓｏｌｕｔｉｏｎ　ｏｆ　Ｆｌｏｗ　Ｆｉｅｌｄ　Ｄｉａｇｎｏｓｉｓ　Ｐｒｏｂｌｅｍ　ｉｎ　Ｍｕｌｔｉｓｔａｇｅ　Ａｘｉａｌ　ＣｏｍｐｒｅｓｓｏｒｓＮｕｍｅｒｉｃａｌＳｏｌｕｔｉｏｎｏｆＦｌｏｗＦｉｅｌｄＤｉａｇｎｏｓｉｓＰｒｏｂｌｅ...     

Vortex Simulation of Axisymmetrical Flows in Cylindrical Geometries．PartI：Numerical Algorithm

ＶｏｒｔｅｘＳｉｍｕｌａｔｉｏｎｏｆＡｘｉｓｙｍｍｅｔｒｉｃａｌＦｌｏｗｓｉｎＣｙｌｉｎｄｒｉｃａｌＧｅｏｍｅｔｒｉｅｓ．ＰａｒｔＩ：ＮｕｍｅｒｉｃａｌＡｌｇｏｒｉｔｈｍ￥ＡｎｄｒＧｉｏｖａｎｎｉｎｉ（ＵｎｉｖｅｒｓｉｔｅＰａｕｌＳａｂａｔｉｅｒａｎ...     

Vortex Simulation of Axisymmetrical Flows in Cylindrical Geometries．PartII：Application to Pipes Incorporating an Orifice Plate

ＶｏｒｔｅｘＳｉｍｕｌａｔｉｏｎｏｆＡｘｉｓｙｍｍｅｔｒｉｃａｌＦｌｏｗｓｉｎＣｙｌｉｎｄｒｉｃａｌＧｅｏｍｅｔｒｉｅｓ．ＰａｒｔＩＩ：ＡｐｐｌｉｃａｔｉｏｎｔｏＰｉｐｅｓＩｎｃｏｒｐｏｒａｔｉｎｇａｎＯｒｉｆｉｃｅＰｌａｔｅ￥ＡｎｄｒＧｉｏｖａｎｎ...     

Analysis of a Coal Fired Combined Cycle with Carried—Heat Gasification

ＡｎａｌｙｓｉｓｏｆａＣｏａｌＦｉｒｅｄＣｏｍｂｉｎｅｄＣｙｃｌｅｗｉｔｈＣａｒｒｉｅｄ－ＨｅａｔＧａｓｉｆｉｃａｔｉｏｎ￥ＸｕＸｉａｎｇｄｏｎｇ；ＺｈｕＷｅｉｍｉｎＺｈａｏＬｉ（ＤｅｐｅｄｍｅｎｔｏｆＴｈｅｒｍａｌＥｎｇｉｎｅｅｒｉｎｇ，Ｔｓｉｎｇ...     

超音速分离管中水蒸气凝结相变的数值研究

基于超音速分离管中混合气体流动属于伴随凝结相变的可压缩、跨音速的特点,建立了考虑传质效应与非平衡凝结过程的数学模型,并采用数值方法对伴随水蒸气凝结的超音速分离管中的流动进行分析研究。以空气、水蒸气及液态水为流动介质,采用两相流动中的VOF模型结合凝结相变模型以及组分传输模型,研究不同进出口参数及不同水蒸气含量对凝结流场的影响。研究结果表明,所建立的分离管内部非平衡凝结相变模型可以较好的再现超音速流中的凝结成核及液滴生长过程;数值计算结果表明,入口压力、温度及水蒸气含量对分离管内流动凝结过程有直接且重要的影响。因此在进行超音速分离管设计时,考虑温度压力参数的同时,考虑水蒸气含量对分离管性能的影响也是非常重要的。     

Study on Characteristics of Steady Flow Condensation Heat Transfer in a Fube Under Zero—Gravitation

ＳｔｕｄｙｏｎＣｈａｒａｃｔｅｒｉｓｔｉｃｓｏｆＳｔｅａｄｙＦｌｏｗＣｏｎｄｅｎｓａｔｉｏｎＨｅａｔＴｒａｎｓｆｅｒｉｎａＴｕｂｅｕｎｄｅｒＺｅｒｏ－ＧｒａｖｉｔａｔｉｏｎＱｎＷｅｉ（ＨａｒｂｉｎＩｎｓｔｉｔｕｔｅｏｆＴｅｃｈｎｏｌｏｇｙ，Ｈａｒｂｉ...     

Effect of uniform suction on laminar filmwise condensation on a finite-size horizontal flat surface in a porous medium

The theoretical analysis of filmwise condensation outside a finite-size horizontal flat surface embedded in a porous medium filled with a dry saturated vapor has been solved by a boundary layer treatment. The Newton-Raphson scheme was employed to solve the finite-size horizontal flat plate in porous medium. Results turns out that the average Nusselt number for condensation heat transfer is expressed in terms of Darcy number, Jakob number, film liquid Prandtl number, Darcy-modified Rayleigh number and the parameter of suction, as well as are given for the condensate layer thickness profiles.     

两相流超音速流动_激波及其应用研究

从两相流体的音速特点出发 ,研究两相超音速流动 ,分析超音速流动导致的激波状况 ,并利用两相激波加速凝结和增压的特点 ,设计了增压换热器。两相流的音速受其压缩性的影响而呈现出与单相流不同的特点 ,其较小的音速值使得两相超音速流动更易实现。两相流激波与波前马赫数密切相关 ,波后汽相凝结、压力升高 ,利用该特点设计的汽水直接接触式换热器 ,具有高效换热和增压的特点     

Phase-transition radiation in vapor condensation process

Energy release by radiative relaxation during water vapor condensation is considered to be responsible for phase-transition radiation in the water vapor condensation process. A two-level transition model is proposed to explain the radiative transfer mechanism for condensation radiation of water vapor. The absorption coefficient due to condensation radiation and the associated optical properties are defined in the radiative transfer equation. The spectral profile of the source function of vapor condensation radiation is examined and agreement with the experimental characteristic wavelength of condensation radiation is found.     

Numerical and analytical study of laminar film condensation in upward and downward vapor flows

Abstract

Laminar film condensation in upward and downward vapor flows is numerically investigated by using a sharp-interface level-set method to track the condensate film surface and accurately calculating the phase-change mass flux under the saturation temperature condition at the interface. An analytical model for steady laminar film condensation in upward as well as downward vapor flows is developed to validate the present numerical results. As the vapor velocity increases, the condensation rate is observed to decrease in upward vapor flows whereas it increases in downward vapor flows. The effects of vapor velocity and wall temperature on laminar film condensation in upward and downward vapor flows are investigated.     

Characteristic curves and the promotion effect of ethanol addition on steam condensation heat transfer

Although most previous studies concerning the condensation of binary vapor mixtures report the condensation rates to be less than that for pure vapor, heat transfer enhancement can be realized by using additives to form a positive system (solutal Marangoni condensation). The objective of the present study was to clarify the effect of mixing ethanol into steam on condensation heat transfer. Precise measurements of the ethanol concentration in the vapor of water-ethanol mixtures were performed over a wide range of ethanol concentrations, and the condensation behavior was observed. The maximum heat transfer coefficients in the condensation characteristic curves were determined to be 0.12 and 0.18 MW/m² K for vapor velocities of 0.4 and 1.5 m/s, respectively, and appeared at an ethanol vapor mass fraction of approximately 1%. The mixing was demonstrated to be extremely effective, particularly in the low-ethanol concentration range. The condensation heat transfer was enhanced approximately 2-8 times compared to pure steam.     

Visualization on flow patterns during condensation of R410A in a vertical rectangular channel

The visualization experiments on HFC R410A condensation in a vertical rectangular channel （14.34mm hydraulic diameter, 160mm length） were investigated. The flow patterns and heat transfer coefficients of condensation in the inlet region were presented in this paper. Better heat transfer performance can be obtained in the inlet region, and flow regime transition in other regions of the channel was also observed. Condensation experiments were carried out at different mass fluxes （ from 1.6 kg/h to 5.2 kg/h） and at saturation temperature 28~ C. It was found that the flow patterns were mainly dominated by gravity at low mass fluxes. The effects of interfacial shear stress on condensate fluctuation are significant for the film condensation at higher mass flux in vertical flow, and con- sequently, the condensation heat transfer coefficient increases with the mass flux in the experimental conditions, The drop formation and growth process of condensation were also observed at considerably low refrigerant vapor flow rate.     

An Experimental Study of Condensation Heat Transfer in Sub-Millimeter Rectangular Tubes

The characteristics of local heat transfer and pressure drops were experimentally investigated using condensing R134a two-phase flow, in single rectangular tubes, with hydraulic diameter of 0.494, 0.658, and 0.972 mm. New experimental techniques were used to measure the in-tube condensation heat transfer coefficient especially for the low heat and mass flows. Tests were performed for a mass flux of 100, 200, 400, and 600 kg/m2s, a heat flux of 5 to 20 kW/m2, and a saturation temperature of 40℃. In this study, effect of heat flux, mass flux, vapor qualities, and hydraulic diameter on flow condensation were investigated and the experimental local condensation heat transfer coefficients and frictional pressure drop are shown. The experimental data of condensation Nusselt number are compared with previous correlations, most of which are proposed for the condensation of pure refrigerant in a relatively large inner diameter round tubes.     

Extensive study on laminar free film condensation from vapor–gas mixture

The dimensionless velocity component method was successfully applied in a depth investigation of laminar free film condensation from a vapor–gas mixture, and the complete similarity transformation of its system of governing partial differential equations was conducted. The set of dimensionless variables of the transformed mathematical model greatly facilitates the analysis and calculation of the velocity, temperature and concentration fields, and heat and mass transfer of the film condensation from the vapor–gas mixture. Meanwhile, three difficult points of analysis related to the reliable analysis and calculation of heat and mass transfer for the film condensation from the vapor–gas mixture were overcome. They include: (i) correct determination of the interfacial vapor condensate saturated temperature; (ii) reliable treatment of the concentration-dependent densities of vapor–gas mixture, and (iii) rigorously satisfying the whole set of physical matching conditions at the liquid–vapor interface. Furthermore, the critical bulk vapor mass fraction for condensation was proposed, and evaluated for the film condensation from the water vapor–air mixture, and the useful methods in treatment of temperature-dependent physical properties of liquids and gases were applied. With these elements in place, the reliable results on analysis and calculation of heat and mass transfer of the film condensation from the vapor–gas mixture were achieved.The laminar free film condensation of water vapor in the presence of air was taken as an example for the numerical calculation. It was confirmed that the presence of the non-condensable gas is a decisive factor in decreasing the heat and mass transfer of the film condensation. It was demonstrated that an increase of the bulk gas mass fraction has the following impacts: an expedited decline in the interfacial vapor condensate saturation temperature; an expedited decrease in the condensate liquid film thickness, the condensate liquid velocity, and the condensate heat and mass transfer. It was found that an increase of the wall temperature will increase the negative effect of the non-condensable gas on heat and mass transfer of the film condensation from the vapor–gas mixture.