Category: Fluid Mechanics And Hydraulic Machines

Example 9.13: A centrifugal pump running at 1,500 rpm has internal and external impeller diameter of 200 and 300 mm, respectively. The vane angles of impeller at inlet and outlet are 25° and 30°, respectively. If water enters the impeller radially and velocity of flow remains constant, determine the work done by the impeller per unit…

Suction Head (hs): It is height of centre (eye) of pump from water level. Delivery Head (hd): It is height of the tank from centre of the pump. Static Head (Hs): It is sum of suction and delivery heads, i.e., Hs = hs + hd. Manometric Head (Hm): It is the head against which a centrifugal pump has to work. where subscript o is used for…

Velocity triangle for centrifugal pump is shown in Figure 9.18. Figure 9.18 Velocity Triangle for Centrifugal Pump Here,

The main components of a centrifugal pump are impeller, casing, suction pipe, foot valve, strainer, delivery pipe, and are discussed below. Impeller: Impeller is a backward curved vane. It is mounted on the shaft coupled to electric motor. Thus, it is a rotating part of centrifugal pump. Casing: It is air tight passage surrounding the pump. Its…

Centrifugal pump works on reverse of the principle of working of radial inward flow reaction turbine. The pressure at the periphery will be high due to centrifugal force on water. The centrifugal force is subjected on water due to forced vortex motion. Water enters in axial direction and leaves in radial direction (Figure 9.16). The…

Working principle of hydraulic pumps is just reverse of the hydraulic turbines. Hydraulic turbine transforms the hydraulic energy into mechanical work whereas hydraulic pump transforms mechanical work into hydraulic energy. The pumps may be reciprocating type or rotary type. Centrifugal pump is a rotary type pump which is used for large delivery and small head…

Governing of turbines is required to control the speed of turbine, since it is coupled with an electric generator with fixed number of poles provided in generator. The speed of turbine is controlled by controlling of water flow. This is done by means of a governor which is running due to motion of shaft of…

Cavitation depends on vapour pressure, absolute or barometric pressure, suction pressure and effective dynamic head, and absolute velocity of water at runner exit.

Cavitation is defined as the phenomenon of formation of vapour bubbles due to fall in pressure below its vapour pressure and sudden bursting of these bubbles in a high pressure zone. It is an undesirable phenomenon.