Q 1Most P.D. compressors are driven by constant-speed motors, becausevariable-speed motors are much more expensive. This poses a problem in controlling the compressor’s How rate. One way to control a compressor with a constant-speed motor is to vary the clearance volume by means of “clearance pockets,” which are connected to or disconnected from the head of the compressor by remotely operated valves. For a 100 percent efficient, adiabatic compressor, what is the effect of such a pocket on the pressure ratio, flow rate, and power requirement?Q 2One of the highest-head water power plants in the world is that at Dixence, Switzerland, with a net head of 5330 ft. The water from this plant drives an impulse turbine (Pelton wheel) with a diameter to the middle of the blades of 10.89 ft. The wheel turns at 500 rpm [10]. What is the ratio of blade speed to jet-speed for this turbine? How does this compare with the optimumQ 3It has been suggested that for short-term service we could make a simple reaction turbine by attaching two solid-fuel rockets to the ends of a rotor. What would the optimum speed for maximum power production be for this type of device? Why does the answer differ from that for the garden-sprinklerEngineering & TechnologyChemical Engineering
