Based on the analysis of tin penetration mechanism in the float glass process, the oxidation model of stannous ion is constructed considering the oxygen activity and the redox reaction in the glass surface layer. The calculation of stannous ion’s oxidation rate makes it possible to predict both stannous and stannic ion’s concentrations independently. And it is also the necessary precondition for the numerical verification of tin penetration mechanism. Coupled diffusion simulation method is established to simulate the penetration process of both stannous and stannic ions simultaneously. The result shows that when the green glass is formed in the reducing atmosphere in tin bath, the stannic ion is accumulated at the position where oxygen activity changes sharply. Satellite peak (internal local concentration maximum) occurs in the tin concentration profile of green glass, which is quite different from that in low iron glass. Compared with gradually cooling temperature regulation, the tin penetrated shifts to greater depth and the depth and magnitude of the satellite peak also increase when reheating temperature regulation is applied. In order to reduce the amount of penetrated tin, the residual time in the high temperature region should be shortened.

Based on the analysis of float glass manufacture process,the flow and heat transfer model of atmosphere in the interior space of tin bath is established.The flow and heat transfer of atmosphere were carried out considering the thermal radiation among the glass ribbon,heater,cooler and the bath wall.The result shows that the heater and cooler have a significant convection effect on the gas nearby,the inner wall has a high temperature with the thermal radiation of heater.The atmosphere in the lower half space moves towards the end of tin bath under the traction effect of glass ribbon.Back flow is observed in the upper space when high traction speed is applied.And the size of the back flow is determined by the traction velocity.In order to avoid the fluctuations and cross region heating,dividing equipments should be arranged to separate the space.

通过分析浮法玻璃渗锡机理,综合考虑玻璃内部氧活度及锡的氧化还原反应,建立了亚锡离子氧化模型计算亚锡离子转化为锡离子的速率,为两种离子浓度分布的独立预测及渗锡机理的数值方法验证提供了条件.在此基础上,建立了扩散过程的耦合数值模拟方法,同步模拟了两种离子的渗透过程.结果表明:高铁含量玻璃在锡槽的还原性气氛中,氧活度剧变处发生了锡离子的积聚,渗锡分布出现卫星峰,而低铁含量玻璃无该现象.与徐冷法相比,锡槽内采用加热重热温度制度,渗锡量、渗锡深度更高,卫星峰向深度方向迁移.为了控制渗锡量,应减少玻璃在高温区停留时间.

The flat glass produced by the float glass process has a tin-rich surface due to the contact with molten tin. The penetration of tin into the glass surface is assumed to involve coupled diffusion of stannous (Sn 2+ ) and stannic (Sn 4+ ) ions. The diffusion coefficients of these ions were calculated using the modified Stocks–Einstein relation with the oxidation velocity of stannous ions depending on the oxygen activity in the glass. The ion diffusion was analyzed using a coupled diffusion simulation with a modified diffusion coefficient to compensate for the negative effect of the glass ribbon’s stretching or compressing in the glass forming process. Tin penetration simulations for both green glass and clear glass show an internal local tin concentration maximum in green glass which is quite different from that in clear glass. The local maximum in the profile is associated with the accumulation of stannic ions where the greatest oxygen activity gradient occurs. Since more float time is needed in the manufacture of thicker glass plate, the tin penetrates to a greater depth with the maximum deeper in the glass and the size of the maximum larger for thicker glass.

Based on the analysis of the float glass production technology, a mathematic model of glass melt flow in the forming process is established. Continuous surface force method (CSF) is used to calculate the surface force on the glass free surface. And the property sudden variation is treated as continuity by continuous transfer treatment method (CTT) at the interface. Robustness of the numerical simulation is improved. Then, free surfaces between the glass melt, molten tin and protective gas are reconstructed by piecewise linear interface construction (PLIC), the movement of glass melt is also tracked. Pilkington tin bath entrances with different lip brick slope are simulated. The result shows that PLIC method can obtain high precision free interface. Back flow exists after the glass melt dropping into the tin bath, and this part of glass melt becomes stagnant flow, and the longer stay of the glass at the high temperature region is easy to result in quality defect. In order to avoid the direct contact with the firebrick, sufficient stagnant region should be provided.

Tin bath is the most important equipment in float glass formation, and the glass quality depends mainly on the temperature control of the glass ribbon. Based on the analysis of tin bath formation technology, a mathematic model is set up in order to investigate the radiative heating effect of SiC heater in the formation process. The view factors are difficult to calculate using the classical method because of the heaters, coolers and other components are sheltered by each other. Therefore, Monte Carlo method is used to calculate the radiation transfer coefficient in which emission, absorption, reflection and other probability models are set up. The motion of rays are tracked in the tin bath and the radiation transfer coefficients between various surfaces are obtained by statistics of large amount of rays' destine. The thermal radiation effect of SiC heater on the glass ribbon is calculated. Lower cost is always the goal of float glass production. Minimum economic loss which combines the glass quality and the electricity input is built up to evaluate the heating effect of SiC heater array. The heaters' surface temperatures are set to be the optimized variables, and they are optimized by Genetic Algorithm (GA). The result accesses to the minimum heater array's energy input while ensuring the glass quality. The heaters at the first row should be priority used, and the heaters close to the center should be set at a higher load.

Based on the analysis of the float glass production technology,a mathematic model of liquid glass in spread process is established.Free surfaces exist between glass,protect gas and liquid tin.Large amount of calculation is required in surface tracing and reconstructing,and the boundary conditions are difficult to determine.Combining the simulation accuracy and efficiency of the method, free surface height marks-SIMPLE Algorithm is established.Actual space of glass is determined by empirical formula,then,corresponding velocity and temperature boundary is determined,and the temperature and velocity field of glass can be calculated by three dimensional SIMPLE Algorithm. The spread process in 400 t/d tin bath is simulated by this method.The temperature field shows that large horizontal temperature difference exists which has negative effect on polishing and smoothing, reasonable arrangement position of cooler is required to reduce the temperature difference in the liquid glass.

As the main influencing factors for instability of film lines are widely used in microelectromechanical systems, buckle-driven delamination and electromigration of film lines on polymer substrate under electrical loading are reported in this letter. The critical buckling condition is obtained through Euler formula. In addition, postbuckling analysis for the film is derived to calculate the residual stress distribution. Both electromigration and buckling stress control the film fracture. Film buckling depends not only on the thermal mismatch between the film line and the substrate but also on the applied electrical loading.

The outside tube heat transfer performance of the discrete double inclined ribs(DDIR) tube was experimentally and numerically studied.Due to the inclined dimple on the outside surface of the DDIR tube,longitudinal vortex formed in the annuli composed of a DDIR tube and a smooth tube.Compared with a smooth annuli,the heat transfer is enhanced 50% and the pressure drop is increased 60%～70% at Reynolds numbers between 30,000 and 90,000.

建立了具有32×16节点电阻的电热模拟装置.每个节点的4个电阻可以通过并联低阻值电阻模拟在基材中填充高导热材料.实验表明,使导热性能最优的高导热材料分布与数值模拟结果相一致,从而进一步验证了导热优化的(火积)耗散极值(最小热阻)原理.实验还证明在一般情况下导热过程的优化不宜采用最小熵产原理,因为后者属于热力学优化原理,适用于热功转换过程的优化.

A new concept in heat transfer together with a new physical quantity characterized by the capacity of heat transfer called ENTRANSPY has been introduced.Entranspy with its adjoint dissipation is closely characteristic of not only the quantity but also the quality(temperature) of thermal energy in heat transfer.This means that the higher entranspy it is,the better heat transfer ability would be.In order to save more energy in glass melting processes,the thermal energy should be classified and used according to the levels of its entranspy.Only when thermal energy is arranged to use for glass melting process based on entranspy can energy-saving be significantly improved by prevention against incorrect allocation of energy in the melting processes.

实验研究了微肋管在过渡区及湍流区的换热及阻力性能,并针对微肋管在过渡区的换热强化较差的特点改进其结构.实验结果表明,改进后的微肋管在2300＜Re＜10000时比原微肋管强化换热提高120%,阻力增加70%～120%.

Experiments were conducted in a sub-scale model room to analyze the influence of wall temperatures on the indoor air flow for different diffuser locations,air jet directions and temperatures.Indoor air flow patterns,velocities and a model of the overall heat transfer rates were obtained for various work conditions using fluid visualizations and quantitative measurements.The results show that the length of the horizontal air jet is reduced as the intake air temperature decreases and that when the eddies caused by the vertical air jet are closer to the wall,the heat transfer is increased by the enhanced natural convection from the lifting force.The air jet is defected to the left for vertical ventilation jets in the center and to the right for jets on the right with lower intake air temperatures.

Experiments are carried out on the convection inside a novel alternating elliptical axis tube. The unified correlations of heat transfer and flow resistance for 500<Re<5×104 are obtained from the experimental results. The experiments show that the heat transfer can be greatly enhanced with less flow resistance increment compared with other enhanced elements. Analyses indicate that the mechanism for heat transfer enhancement is mainly due to the effect of the multi-longitudinal vortices induced by the cross-sectional change in the alternating elliptical axis tubes.

A new method is developed for the discretization of the complex structure of the spirally inner finned tubes. High quality hex mesh was adopted which can reduce cell counts and improve the accuracy of simulation. Numerical simulation on the flow and heat transfer in spirally inner finned tubes was done by using Fluent, and the results was in good agreement with the Jensen's experimental data. The performances of the rectangle, triangle, and round crest inner fins with same fin height, width and helix angle were numerically compared.

The dependence of the Nusselt number on the time-averaged velocity and temperature fields was derived for turbulent convective heat transfer to show that the field coordination principle is also suitable for turbulent convective heat transfer. The features of convective heat transfer in tubes and the field coordination principle was used to develop an enhanced heat transfer tube the alternating elliptical axis tube. The numerical and experimental results show that heat transfer is markedly enhanced with less additional flow drag than the other enhanced tube designs.

本文将探索应用减压膜蒸馏技术制取纯净水,同时采用压缩式热泵回收水蒸气冷凝潜热用于加热原料液,以提高能源利用率的可行性.压缩式热泵系统以R142b为工质,在热源(原料液)温度为55～65℃、冷源(水蒸气)温度为30～50℃的条件下,系统的COP可达3.0以上,系统单耗173 Wh/kg.与TIMES[1]相比,不仅提高了产水率,而且明显降低了系统的单耗.指出了进一步降低制冷温差,提高系统运行经济性的技术途径.

对交叉缩放椭圆管进行了实验和数值研究,给出了换热和沿程阻力系数实验拟合关联式。交叉缩放椭圆管管内 截面交叉变化诱导产生强烈的二次流和纵向涡流,改善了速度场与温度场之间的协同关系。实验和数值模拟结果表明,交 叉缩放椭圆管管内的流动在Re≥500即表现为湍流,换热强化效果显著。

本文提出了一种较准确测量管外壁面温度的热电偶埋设方法,实验研究了交叉椭圆管的管内换热性能.结果表明,该方法可较好的将管外换热热阻分离开来,实现异形管内换热性能的测试.

导出管内湍流换热Nu与局域时均参数的关系式,将对流换热的场协同理论扩展至湍流换热.分析了管内对流换热的特点,并根据场协同理论提出强化湍流换热的方法,发展了一种新型强化换热管-交叉椭圆管,既适合于层流换热强化也适合于湍流换热强化,其强化传热效果显著而流阻较小.