变水头大流量标准装置系统的数值分析

本文从流体力学基本原理出发,建立了变水头大流量标准装置流体流动的基本微分方程,运用Runge-Kutta方法求出了在水柜直径D=10m,8m,5m;水柜高度H_o=20m;试验管道直径d=1.2m等条件下用变水头大流量标准装置校验电磁流量计的一次近似解。计算结果表明,在阀门开启一段时间后,变水头大流量标准装置中水柜液面高度随时间成二次方关系变化;水柜液面下降的速度及试验管道中液体流量随时间的变化率为常值。利用上述特性有可能使用变水头大流量标准装置检定大口径流量仪表。本文对使用的方法进行了初步探讨,并讨论了变水头大流量标准装置的一些其它特性。

The Mathematical Analysis for the System of Variable Head Standard Device for Large Flow Rate

The object of this contribution is to develop the principle of a new type calibration device for water flow rate-the variable water head standard device. Based on the basic principle of fluid mechanics, the authors present the mode of the device, differential equation and the solution under the conditions as follows: the diameter of the pipe and the tank are: d =1.2m, D= 10m, 8m, 5m separately, the height of the tank H_0 = 20m. and there is a magnetic flowmeter in the pipeline. The resuhs of computation demonstrate that in all cases after the valve is opened for a period of time, the change rate of discharge in the pipes is constant. By virtue of it, we might use this device to calibrate the large flowmeters by water.Finally, some other characteristics of the variable water head standard device for large flow rate have been dealt with and theoretically investigated.