Author: haroonkhan

Single row of nozzle with single row of blade is called one stage of turbine. If steam at very high pressure is allowed to expand in single stage of turbine, the blade velocity will be too high. Such a high rotational speed cannot be used properly and also there will be velocity loss at the…

In the impulse turbine, all the pressure drops occur in nozzle and there is no pressure drop of steam passing through blades. Let us consider steam enters the nozzle with pressure of P0 and velocity of V0, after expansion of steam in nozzle pressure drops to P1 and velocity increases to V1. High velocity jet of steam impinges on the blades…

If torque produced on the shaft of the turbine is only due to change in momentum of steam and pressure of steam at inlet and outlet of the turbine being same, it is known as impulse turbine. In this turbine, the expansion of high-pressure steam occurs only in nozzle as shown in Figure 5.8a, b. During…

Broadly, steam turbine can be classified into two categories as follows: Pure reaction turbine cannot be used for practical purpose; therefore, impulse-reaction turbine is referred as reaction turbine.

Steam turbine is a prime mover, which converts heat energy of steam into mechanical energy by rotating motion of the blade. Total energy conversion involves two types of steam expansion—expansion of steam in nozzle and expansion of steam in turbine blades. The function of steam engine and steam turbine are similar, but steam engine converts…

The flow diagram of a steam power plant is shown in Figure 5.7. Figure 5.7 Flow Diagram of Power Plant Suppose Qin Heat supplied to water in turbine Qout Heat librated in condenser Wpump Work done on pump Wturbine Work done by turbine The thermal efficiency of Rankine cycle can be given as

There are four important processes in the Rankine cycle. These states are identified by numbers as shown in Figure 5.6. Figure 5.6 Rankine Cycle Process 1–2 (Pumping Process): The working fluid is pumped from low pressure to high pressure, as the fluid is a liquid at this stage the pump requires some small amount of input energy. Process…

The Rankine cycle is the most commonly used cycle in thermal power plants—steam engine and steam turbines. The Rankine cycle is sometimes referred to a practical Carnot cycle because when an efficient turbine is used, the T–s diagram begins to resemble the Carnot cycle. The main difference is that heat addition and rejection are at constant pressure…

Actual indicator diagram is shown in Figure 5.5. In this diagram, points 1, 2, 3, 4 and 5 show actual admission pressure, point of cut-off, point of release, point of closing the exhaust port and starting of compression, and point of opening of admission port, respectively. The area of actual indicator diagram is less than the…

Theoretical indicator diagram for a steam engine is shown in Figure 5.3 without clearance volume and with clearance volume in Figure 5.4. In Figure 5.3, clearance volume is zero. Steam at boiler pressure enters into the cylinder at point 1 and cut-off at point 2. Then the steam expands inside the cylinder isothermally from point 2 to point 3. Point 3…