Category: Advance Concept Mechanical Eng

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.

Area of flow at inlet = , where D0 is outer diameter of runner and Db is hub diameter. Velocity triangle is similar to velocity triangle of Francis turbine. Only difference is that the velocity of flow at inlet and outlet in Kaplan turbine is same as shown in Figure 9.15. Figure 9.15 Velocity Triangle for Kaplan Turbine Velocity of flow at…

Kaplan turbine is an axial flow, low head, high specific speed, reaction type turbine. There is a similar turbine known as propeller turbine having fixed vane in place of adjustable vane as in Kaplan turbine. Kaplan turbine has the following components (Figures 9.13 and 9.14): Figure 9.13 Main Components of Kaplan Turbine Figure 9.14 Kaplan Turbine Scroll Casing: Its function…

Velocity triangle for Francis turbine is shown in Figure 9.12. Figure 9.12 Velocity Triangle for Francis Turbine Here, The work done per second on runner by water, The work done per second per unit weight of water =  where +ve sign is taken if β < 90; −ve sign is taken if β > 90, and Vω2 = 0, if β = 90. In case…

Figure 9.11 shows the different shapes for draft tubes. Figure 9.11 Different Types of Draft Tubes