| 摘要 |
PURPOSE:To minimize the delivery pressure loss of the screw compressor by a method wherein a delivery port is provided at a position whereat the pressure ratio at the position of the delivery port, determined by the position of the delivery port, becomes smaller than a disigned operating pressure ratio. CONSTITUTION:An affection of the delivery pressure loss to the efficiency of the compressor is increased as the operating pressure ratio pi of the compressor and the peripheral speed U of a rotor are increasing, therefore, the delivery port is opened in the compression process, having large operating pressure ratio and the peripheral speed U of the rotor, at a position whereat the pressure ratio pii at the position of the delivery port becomes smaller than the operating pressure ratio. Accordingly, a formula, in which the maximum compression efficiency is obtained, becomes the formula as shown. Here, (a) represents the sonic speed of the gas under a suction condition, UM represents the peripheral speed of the male rotor, pii represents the pressure ratio at the position of the delivery port and pi represents the operating pressure ratio. |
