Numerical Modeling of Heat and Mass Transfer in a Low-Temperature Heat Pipe

A mathematical model of heat and mass transfer in a low-temperature heat pipe has been formulated. Numerical modeling of the problem of heat and mass transfer has been carried out. The distributions of the velocities, the pressure, and the temperatures in the heat pipe have been obtained. The results can be employed in analyzing the efficiency and power of low-temperature heat pipes.     

Heat and Mass Transfer in Anisotropic Bodies

This review is aimed, on the one hand, at attracting the researchers' attention to the problems associated with heat transfer in anisotropic bodies and, on the other hand, at analyzing the scanty experience in investigating the heat transfer in anisotropic bodies that has been accumulated over the last 30 years. We treat conjugate heat transfer between boundary layers and anisotropic bodies, and heat transfer under conditions of simultaneous reciprocal influence of anisotropic thermal conductivity and anisotropic filtration upon film cooling of bodies with anisotropic properties. New effects are revealed during simulation of conjugate heat transfer; the law of nonlinear filtration in anisotropic bodies is identified; and the effect of individual components and of the orientation of the principal axes of thermal conductivity and penetrability tensors on stationary temperature fields and on the distribution of components of the filtration rate is investigated. The results of analytical investigation of heat transfer in anisotropic bodies enables one, under conditions of lack of adequate information, to exactly simulate nonstationary temperature in simplest anisotropic bodies, which may be used as test results. A number of recommendations are formulated for implementation of heat shielding of anisotropic bodies under conditions of their aerogasdynamic heating.     

Nonstationary Heat and Mass Transfer in Molecular Gases

The analytical solution of the problem on a nonstationary heat source in a diatomic gas has been given. The characteristics of the temperature and sound waves excited by it have been obtained. The distribution of the pressure, temperature, and concentration of the gas molecules has been considered.     

湿膜加湿器热质交换过程分析

湿膜加湿器是利用直接蒸发加湿的工作原理,对空气进行加湿,只消耗风机和循环水泵的电耗,具有结构简单和节省能源的优点。本文根据热质交换理论对湿膜加湿的传质过程进行了理论分析,建立了湿膜加湿器的传热、传质微分方程,得出影响加湿量的主要因素,并讨论了它们的影响趋势。     

Heat and Mass Transfer Measurements for Tray-Fermented Fungal Products

In this study, heat and mass transfer in static tray fermentation, which is widely used in solid-state fermentation (SSF) to produce fungal products, such as enzymes or koji, is investigated. Specifically, kinetic models of transport phenomena in the whole-tray chamber are emphasized. The effects of temperature, moisture, and humidity on microbial growth in large-scale static tray fermentation are essential to scale-up SSF and achieve uniform fermentation. In addition, heat and mass transfer of static tray fermentation of Trichoderma fungi with two tray setups??traditional linen coverings and stacks in a temperature?Chumidity chamber is examined. In both these setups, the following factors of fermentation were measured: air velocity, air temperature, illumination, pH, carbon dioxide (CO₂) concentration, and substrate temperature, and the effects of bed height, moisture of substrate, and relative humidity of air are studied. A thin (1 cm) bed at 28 °C and 95 % relative humidity is found to be optimum. Furthermore, mixing was essential for achieving uniform fermentation of Trichoderma fungi. This study has important applications in large-scale static tray fermentation of fungi.     

Mathematical Modeling of Heat and Mass Transfer in Evaporation of a Substance from a Porous Body in Vacuum

A problem of the Stefan type which describes heat and mass transfer in a porous body with the double phase transition liquid–ice–vapor has been formulated and solved.     

Hybrid Approach to Modeling the Process of Convective Radiative Heat and Mass Transfer in Closed Differentially Heated Cavities

Journal of Engineering Physics and Thermophysics - A hybrid model has been developed for the analysis of the process of combined mass and heat transfer in closed rectangular cavities under the...     

Action of Vibrations on Heat and Mass Transfer in Boiling

The state of the art of the works known in the literature and concerned with the influence of vibrations of structures of plants and artificially initiated vibrations in working liquids on the processes involving boiling is analyzed. The authors discuss theoretical and experimental results on the influence of frequencies and amplitudes on the internal characteristics of boiling, namely, the initiation of a vapor phase, the superheat in boiling, the growth and separation of vapor bubbles and the frequency of their occurrence, the density of nucleation sites, and also on the value of the heat fluxes and on the heattransfer coefficient. Application of vibrational actions for intensification of heat and masstransfer processes is shown to be promising.     

Influence of Heat and Mass Transfer on Wood Impregnation Kinetics

We have further developed the nonstationary mathematical model of twophase filtration in an anisotropic porous medium — wood — by a fluid, taking into account the temperature dependence of its viscosity. The results of the calculations of the temperature and kinetics of wood impregnation under the action of vacuum and excess pressure for the problem of internal and external heat transfer are presented. The process of preservative impregnation of woodworks with a wateroil emulsion for various degrees of filling of the autoclave, including the maximum one, has been simulated.     

Multi-scale Numerical Modeling of Radial Heat Transfer in Grooved Heat Pipe Evaporators

It is well known that small-scale effects near contact lines have a crucial importance on the radial heat transfer within a grooved heat pipe evaporator. This paper studies this problem using a multi-scale model which is composed of two parts, macroscopic and microscopic. At the macroscopic scale, we solve the heat conduction problem for the solid and the liquid phases, using a finite-element method. In order to avoid the classical singularity problem at the contact line, in addition to taking the solid thermal conductivity into account, we do not impose the saturation temperature but a mixed condition along the interface. The coupling with the microscopic scales is achieved using a correlation for the apparent contact angle, obtained from a lubrication-type theory developed for the contact line region, and taking into account the variation of the saturation temperature with the disjoining pressure and with the meniscus curvature. Our results show a strong influence of this apparent contact angle on the heat transfer within the heat pipe, for two different geometries and as a function of the heat flux.     

热回收型热管式间接蒸发冷却器的传热传质机理及优化设计

本文分析了热管式间接蒸发冷却器的传热传质机理。运用能量守恒定律及传热学的研究方法,对热管间接蒸发冷却器进行传热传质实验研究,并根据运行参数对冷却效率的影响,提出了增强换热传质,提高换热效率E的方法,为优化设计热管间接蒸发冷却器提供了理论与技术依据。     

Modeling of Laws Governing Heat Transfer in Sliding Bearings

A technique for determining temperatures arising in sliding bearings during operation is presented. Results of the calculation of the level of temperatures in the bearing by the suggested mathematical model depending on the operating conditions and results of their experimental verification are given. The difference between them is slight.