Hydraulic Machines Questions

• In a Francis turbine runner, the number of blades are generally between
• The depth of the bucket for a Pelton wheel is generally __________ the diameter of jet.
• The force exerted (in newton) by a jetof water impinging normally on a fixed plate is (where w = Specific weight of water in N/m3, a = Cross-sectional area of jet in m2, and V = Velocity of jet in m/s)
• The relation between hydraulic efficiency (ηh), mechanical efficiency (ηm) and overall efficiency (ηo) ) is
• The maximum hydraulic efficiency of an impulse turbine is (where φ = Angle of blade tip at outlet)
• The specific speed of a turbine is given by the equation
• The hydraulic efficiency of a reaction turbine, is the ratio of
• A Pelton wheel develops 1750 kW under a head of 100 metres while running at 200 r.p.m. and discharging 2500 litres of water per second. The unit speed of the wheel is
• A Pelton wheel is
• A Pelton wheel with one nozzle is preferred for a specific speed between 35 to 60 r.p.m.
• Delivery head of a centrifugal pump is
• The specific speed of a hydraulic turbine depends upon
• Power required (in watts) to drive a centrifugal pump is (where Hm = Manometric head in metres, w = Specific weight in N/m3, Q = Discharge of the pump in m3/s, and ηo = Overall efficiency of the pump)
• By fitting an air vessel to the reciprocating pump, there is always a saving of work done and subsequently saving of power.The saving in case of a double acting reciprocating pump is
• An impulse turbine is used for
• In a centrifugal pump, the water enters the impeller __________ and leaves the vanes axially.
• The impeller of a centrifugal pump may have
• Kinematic similarity is said to exist between the model and the prototype, if both of them
• In order to avoid cavitation in centrifugal pumps
• A reciprocating pump is suitable for less discharge and higher heads.