Regenerative turbine pump

A regenerative (turbine) pump has the water head-capacity and power-input characteristics shown in Fig. 6.34. Determine the head-capacity and power-input characteristics for four different viscosity oils to be handled by the pump—400, 600, 900, and 1000 SSU. What effect does increased viscosity have on the performance of the pump ... 

Kinetic. Kinetic pumps, which act by impelling a fluid from one location to another, can be centrifugal, regenerative turbine, or special effect (see Fig. 1). 

Mechanical Impulse The principle of mechanical impulse when applied to fluids is usually combined with one of the other means of imparting motion. As mentioned earher, this is the case in axial-flow compressors and pumps. The turbine or regenerative-type pump is another device which functions partially oy mechanical impulse. 

The majority of centrifugal pumps have performance curves with the aforementioned profiles. Of course, special design pumps have curves with variations. Eor example, positive displacement pumps, multi-stage pumps, regenerative turbine type pumps, and pumps with a high specific speed (Ns) fall outside the norm. But you ll find that the standard pump curve profiles are applicable to about 95% of all pumps in the majority of industrial plants. The important thing is to become familiar with pump curves and know how to interpret the information. 

Turbine pumps [Figs. 7.9(f), 7.12(i), and 7.4(a)] also are called regenerative or peripheral. They are primarily for small capacity and high pressure service. In some ranges they are more efficient than centrifugals. Because of their high suction lifts they are suited to handling volatile liquids. They are not suited to viscous liquids or abrasive slurries. 

Most large generator designs also incorporate a regenerative FW heating facility where from 20 to 30% of the throttle steam may be withdrawn from the turbine at various points to provide the necessary heating. In addition, the primary steam requirement for the FW pump turbines is extracted from the main turbine at the IP to LP crossover point. 

Determine the efficiency and power output of a regenerative Rankine cycle using steam as the working fluid and a condenser pressure of 80 kPa. The boiler pressure is 3 MPa. The steam leaves the boiler at 400° C. The mass rate of steam flow is 1 kg/sec. The pump efficiency is 85% and the turbine efficiency is 88%. After expansion in the high-pressure turbine to 400 kPa, some of the steam is extracted from the turbine exit for the purpose of heating the feed-water in an open feed-water heater, the rest of the steam is reheated to 400°C and then expanded in the low-pressure turbine to the condenser. The water leaves the open feed-water heater at 400 kPa as saturated liquid. Determine the steam fraction extracted from the turbine exit, cycle efficiency, and net power output of the cycle. 

A steam power plant operating on a regenerative cycle, as illustrated in Fig. 8.5, include feedwater heaters. Steam enters the turbine at 6,000 kPa and 500°C and exhausts at 10 kPa. St for the feedwater heaters is extracted from the turbine at pressures such that the feedwater is he to 180°C in two equal increments of temperature rise, with 5-°C approaches to the steam-condensa temperature in each feedwater heater. If the turbine and pump efficiencies are both 80 percent, is the thermal efficiency of the cycle and what fraction of the steam entering the turbine is extra for each feedwater heater ... 

In this ideal regenerative Rankine cycle, the steam extracted from the turbine heats the water from the condenser, and the water is pumped to the boiler. Sometimes, this occurs in several stages. The condensate from the feed water heaters is throttled to the next heater at lower pressure. The condensate of the final heater is flashed into the condenser... 

A steam power plant is using an actual regenerative Rankine cycle. Steam enters the high-pressure turbine at ll,000kPa and 773.15K, and the condenser operates at lOkPa. The steam is extracted from the turbine at 475 kPa to heat the water in an open heater. The water is a saturated liquid after leaving the water heater. The work output of the turbine is 90 MW. The pump efficiency is 95% and the turbine efficiency is 75%. Determine the work loss at each unit if the surroundings are at 290 K. 

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