WATER MIST FLOW IN A SUPERCONDUCTING MAGNET INCLINED AT VARIOUS ANGLES

Water mist (diamagnetic) flow in a superconducting magnet of 10 T at various angles is studied experimentally and numerically. Water mist is produced by ultrasonic atomizers and fed into a cylindrical Plexiglas pipe (inner diameter, 90 mm) placed in a bore space of an inclined superconducting magnet. The water mist is found to stop at some locations in the magnet at inclined angles ψ ≤ π/6. At ψ ≥ π/4, the amount of mist flowing out of the other opening of the pipe increases with an increase in inclined angle. In the computation of this phenomenon, water mist is simulated with 1000 water droplets of 3 μm diameter. Brownian motion is considered and the Langevin equation is solved. The numerical results show that at ψ ≤ π/6, most of the water droplets accumulate above the magnetic coil. However, at ψ ≥ π/4, with an increase in inclined angle, the number of water droplets passing through the magnetic coil increases.     

不同倾角放置螺旋管汽波两相摩擦阻力特性

在宽广的参数范围内试验研究了螺旋管在不同倾角放置时的单相及汽液两相摩擦阻力特性,获得了螺旋管放置方向及各主要系统参数对汽液两相摩擦阻力特性的影响规律。在对试验结果及前人研究结果进行详细分析的基础上,获得了第一个能适用于不同倾角放置螺旋管的单相及汽液两相摩擦阻力计算式,从而为汽液两相摩擦阻力及螺旋管的进一步研究和应用提供了依据。     

A METHOD OF SKIN FRICTION DETERMINATION OF A CIRCULAR CYLINDER IN A WATER FLOW FIELD

Using a partially-heated cylinder with a thin heat transfer sensor, it is clarified that the skin friction coefficient of a cylinder in water can be calculated by the Brown's equation, when the profile of its pressure coefficient has been measured. It is also revealed that the separation angles of the boundary layer on the cylinder surface can be determined by the skin friction profiles. These results are ascertained to be reliable by a flow visualization method.     

荣成万吨级反渗透海水淡化示范工程

本文叙述了荣成万吨级反渗透海水淡化示范工程项目第一期工程的工艺设计，设备配置，系统控制和平面布置的基本情况。通过对该反渗透海水淡化系统的调试和试运行，结果表明该系统运行参数稳定，设备运行正常，性能指标达到设计要求，产品水符合国家生活饮用水标准。根据该项目投资和当地情况，概要地分析了该系统的造水成本，经济和社会效益。     

MHD FREE CONVECTION FLOW OF A NANOFLUID PAST A VERTICAL PLATE IN THE PRESENCE OF HEAT GENERATION OR ABSORPTION EFFECTS

This work is focused on the numerical solution of steady natural convection boundary-layer flow of a nanofluid consisting of a pure fluid with nanoparticles along a permeable vertical plate in the presence of magnetic field, heat generation or absorption, and suction or injection effects. The model used for the nanofluid incorporates the effects of Brownian motion and thermophoresis. The governing boundary-layer equations of the problem are formulated and transformed into a non-similar form. The obtained equations are then solved numerically by an efficient, iterative, tri-diagonal, implicit finite-difference method. Comparisons with previously published work are performed and are found to be in excellent agreement. Representative results for the longitudinal velocity, temperature, and nanoparticle volume fraction profiles as well as the local heat transfer rates for various values of the physical parameters are displayed in both graphical and tabular forms.     

DRYOUT OF WATER FILM ON A HEATED TUBE SURFACE CAUSED BY AN OBSTRUCTION IN A BOILING TWO-PHASE VERTICAL UPWARD FLOW

Due to the increasing consumption of energy and the green house effect caused by C0₂ nudear power stations have been playing more important role than ever in the electric power generation. And both the economy and the safety of the nuclear power station are strongly demanded. One of the restriction in the thermal design of the safe and economic nuclear reactor, especially in BWR is pointed out to be the heat removal from the fuel rods near the rods supporting spacer.

The purpose of the present paper is to investigate the mechanism of the water film breakdown which results in the burnout of heating tube near the spacer under various flow pattern.

The experimental results show that the film breakdown occurs near the leading edge, i.e., just below the spacer, as well as the inside of the down part of the gap between the heating tube and the spacer.