Temperature distribution in a cylindrical lengthy workpiece under plasma electrolytic heating

The article focuses on developing a model of a stationary temperature field inside a semi-infinite cylindrical sample partly immersed in electrolyte. Temperature calculation is carried out by solving a heat transfer equation separately for the immersed and protruding parts of the sample. The heat flux is set on the outer area boundaries; meanwhile heat flux density for the immersed part is linearly dependent on the vertical coordinate. Within the framework of the model, vertical and radial temperature gradients are worked out both in protruding and immersed parts of the anode. It has been established that the vertical coordinate of the sign reversal point of the heat flux density in the immersed part depends on heat exchange conditions in the protruding part.

Conjugate heat transfer in the mode of thermal gravitational-capillary convection in the model of a fuel tank, after a sudden heating of the sidewall

The evolution of unsteady gravitational-capillary convection in a layer of ethyl alcohol with a free surface after sudden electric heating of one of the vertical walls of a rectangular cavity was investigated numerically. The effect of the incoming flow of hot liquid on the time evolution of the temperature field on the opposite thin metal wall of the cavity was investigated. The calculations were carried out by the finite element method in the conjugate two-dimensional formulation with the Prandtl number Pr = 16, and the range of Grashof numbers determined by the heat flux density, 33·103 ≤ Gr ≤ 28·106. It is shown that the maximum local temperature gradients occur on the wall near the liquid-gas interface.

Microchannel Liquid-Cooled Heat Exchanger Based on a Nonuniform Lattice: Study on Structure Calculation, Formation Process, and Boiling Heat Transfer Performance

A microchannel radiator is advantageous due to its high efficiency and large boiling heat transfer coefficient of two-phase flow. Based on the research of uniform lattice structures, this study proposed a microchannel heat exchanger with a nonuniform lattice structure. The calculation, optimal formation, and boiling heat transfer performance of the nonuniform lattice structure based on selective laser melting (SLM) were investigated, and heat exchange samples were successfully prepared using SLM. The porosity and pore morphology of the samples were analysed, and the contrast experiments of boiling heat transfer were conducted with deionised water. The results revealed that the heat flow density of the lattice structure was a minimum of 244% higher than that of the traditional liquid-cooled plate. The critical heat flux density of the lattice structure is 110 W∙cm−2, and the critical heat flux density of the traditional flat plate is 45 W∙cm−2. In addition, the effects of cell structures indicated that for frame cells, the heat transfer effect of nonuniform frames was inferior to that of uniform frames; for face-centred cubic (FCC) cells, the nonuniform and uniform frames exhibited the same trend. However, the heat flow density of FCC cells was 25% higher than that of frame structures.

A Simulation Method for the Optimization of Cooling Water Slot Structure in Slab Continuous Casting Mold Combined With SEN

The temperature field in the full 3D finite element mold model combined with submerged entry nozzle(SEN)(Full SEN-3D FEMM) is simulated with Fluent of ANSYS 18.0 Package to apply the maximum heat flux density on the heat face of mold copper plate obtained through this simulation to the element model of the copper plate, and thermal stress and strain simulations on the copper plate and stainless back ones are conducted with Workbench of ANSYS 18.0 Package to confirm the reasonable designing factors for the water slot structure on the copper plate. The maximum heat flux densities on the wide and narrow heat faces of the copper plates are given on the initial shock areas of molten steel flux injected through SEN. With constant heat flux density on the heat face, the more the thickness of copper plate increases, the more the max- and min temperatures increase and the difference between them decreases. Elastic and plastic deformations on the copper plate are made during continuous casting(CC) process; the former occurs around the water slots and the latter around the heat face with the highest temperature, which regards 20-18-17 as the most reasonable one among 4 plans for the water slot structure.

ANALYSIS OF THE INFLUENCE OF DISTANCE BETWEEN THE HEATING ELEMENT AND THE SAMPLE ON THE SMOKE FORMING ABILITY OF PINE WOOD IN VIETNAM

Series of fire tests was carried out to determine the smoke-forming ability of conifer- ous wood at different distances of the sample from the heating element. It was found that the same heat flux density leads to a difference in temperature at different distances, which significantly affects the test result.

Investigation of the influence of Taylor-Gortler vortexes on heat transfer of annular channel

This article is about the influence of Taylor-Gortler vortices on heat transfer in concentric annular channels with turbulent decaying swirling flows. The study shows that the occurrence and transformation of secondary vortex structures has a significant effect on the distribution of heat flux over the annular channel surface. An explicit is relationship between the radial velocity fluctuations and the heat flux density distribution. The highest intensity of heat transfer on the outer surface is observed in the areas of positive radial velocity values, while on the inner surface it is observed in the areas of negative radial velocity values.

Features of heat and mass transfer at drying of ceramic products with overglaze paints

The basic results of researches of process of a heat exchange are instanced and parsed at drying glasour ceramic colors. Character of change of importance number of Rebinder is established at drying colors and dependence of intensity of a heat dissipation on velocity of air is spotted. The main results of researches of heat and mass transfer process at drying of overglaze ceramic paints in a stream of drying agent are resulted and analyzed. The nature of the change in the value of the Rebinder number for drying paints is established and the dependence of the heat transfer intensity on the air velocity is determined. Analysis of the temperature coefficient of drying and Rebinder's number determined the directions of heat consumption in the drying process of overglaze ceramic paints. It is established that the heat flux density depends on the temperature and velocity of the coolant and does not depend on the chemical composition of the paints. It is shown that the heat transfer coefficient depends on the velocity of the coolant. Compared with heat transfer during laminar flow around the plate during drying, the intensity of heat transfer increases by 75%.