| 摘要 |
PURPOSE:To suppress generation of cavitation and prevent corrosion by allowing the shaft-sealing water in low temperature to gush onto the negative- pressure surface of the vane of a vane wheel and allowing the saturated steam pressure to increase locally. CONSTITUTION:The temperature at ten precents of the inlet area of a vane wheel is reduced by one degree by allowing the cold water in an amount of q at a temperature of 30 deg.C to gush from a cold water jet hole 15 into the fluid at a temperature of 160 deg.C which is sucked into the vane wheel 10. In this case, if the discharge amount from the vane wheel 10 is Q, and the specific heat of the fluid is 1, the difference heat quantity before between and after gushing of the cold water is given in a formula q=0.0008Q. Therefore, the gushing amount q is 0.08% of the discharge amount Q, and nearly equal to the amount of leak from the shaft sealing part. Therefore, the amount of gushing from the jet hole 15 is enough to prevent generation of cavitation without reducing the pump efficiency by utilizing the shaft sealing water. |
