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在静态蒸汽管道中,当阀门刚开启时,流体的流速加快,使阀门上游的蒸汽膨胀。蒸汽一膨胀,压强降低,流体就以波的形式流动,其流速达声速。在这种不稳定状态下,阀门上游的管网弯头之间出现的压差就可产生冲击荷载,该荷载可使管网发生相当大的振动。本文的目的在于寻找表达这种不稳定状态中,阀门上游蒸汽压降与时间的直接函数关系,并预测压降波的波形。
In a static steam pipe, when the valve is open, the flow rate of the fluid is increased, causing the steam upstream of the valve to expand. As soon as the steam expands and the pressure decreases, the fluid flows in the form of a wave whose velocity reaches the speed of sound. In this unstable condition, the pressure differential between pipe bends upstream of the valve creates an impact load that causes considerable vibrations in the pipe network. The purpose of this paper is to find out the direct function of the vapor pressure drop in the upstream of the valve in relation to this instability and to predict the waveform of the pressure drop wave.