Pumps power requirements

Discharge versus pump power requirement, i.e. Q versus... 

Pump power requirements increase with the cube of the speed, so doubling the speed requires eight times the power. 

Phase-change cooling systems make do with smaller sizes without necessarily imposing a larger pumping power requirement compared with single-phase systems. 

COMMENTS The Carnot vapor cycle as illustrated by Example 2.1 is not practical. Difficulties arise in the isentropic processes of the cycle. One difficulty is that the isentropic turbine will have to handle steam of low quality. The impingement of liquid droplets on the turbine blade causes erosion and wear. Another difficulty is the isentropic compression of a liquid-vapor mixture. The two-phase mixture of the steam causes serious cavitation problems during the compression process. Also, since the specific volume of the saturated mixture is high, the pump power required is also very high. Thus, the Carnot vapor cycle is not a realistic model for vapor power cycles. 

In a Rankine power plant, the steam temperature and pressure at the turbine inlet are 1000°F and 2000 psia. The temperature of the condensing steam in the condenser is maintained at 60° F. The power generated by the turbine is 30,000 hp. Assuming all processes to be ideal, determine (1) the pump power required (hp), (2) the mass flow rate, (3) the heat transfer added in the boiler (Btu/hr), (4) the heat transfer removed from the condenser (Btu/hr), and (5) the cycle thermal efficiency (%). 

Find the pump power required, turbine power produced, rate of heat added to the boiler, and the cycle efficiency. 

If the pressure is throttled down to 400psia at the inlet of the turbine, find the pump power required, turbine power produced, rate of heat added to the boiler, rate of heat removed in the condenser, and the cycle efficiency. Draw the T s diagram. 

The power-generating potential of a water-dominated resource depends on the geothermal fluid temperature and production flow rate (Fig. 2). The figure gives the net power output, which accounts for parasitic loads caused by the condenser and feed pump power requirements. The output power from two-phase water-steam or steam alone is much greater than the curves shown for liquid in Fig. 2. 

For extreme intensities, lasers can only be operated in pulsed rather than CW fashion, due to the heating of the cavity and the high pumping power required for the population inversion. Laser pulses with peak powers of 2.5 x 1013 watts have been achieved of course, such a pulse lasts for only a rather short time (10-12 sec). 

The paper discusses operating limitations imposed by the turbine exhaust element and the alternatives presently available to the electric utility industry. It also presents tools for estimating dry tower plot area, fan power and circulating pump power requirements. It shows the savings in fan power which can be expected with a decrease in turbine-generator load and ambient air temperatures. It discusses expected maintenance costs and the owner s possible exposure with a large 1000 MW dry cooling tower system. The paper ends with an evaluation of the potential for lower dry tower system costs in the future. 12 refs, cited. 

Pumping Power Required from Bottom of Absorber to Top of Stripper (Horsepower) Pumping Power Required from Bottom of Stripper to Top of Absorber (Horsepower) Pumping Power of Inlet Gas Blower (Horsepower)... 

A. Pumping Power Required to Transport Fluid from Bottom of Absorber to Top of Stripper... 

With 80% efficiency of the pump, total energy loss is 1.2x10 ft-lb /lb and the pumping power required is... 

Up-conversion and excited state absorption are the main gain-limiting factors in Er111-doped planar optical amplifiers, either glass- or polymer-based. Up-conversion increases the pump power required to achieve a certain degree of population inversion, up to factors... 

M = ratio of total cost for pumping installation to yearly cost of pumping power required... 

The liquid is put into the absorption tower by means of a nozzle at the top of the tower. The pressure just before the nozzle is 35 psig. Assume the pump for the liquid must supply power to lift the liquid to the top of the tower and compress the liquid to 35 psig. Use a 10 percent safety factor on the above pumping-power requirements to take care of the friction in the lines and other minor losses. 

The power required to move a fluid dirough a tube bank is proportional to the pressure drop, and when the pressure drop is available, the pumping power required to overcome flow resistance can be determined from... 

The pumping power requirement for a laminar flow piping system can be reduced by a factor of 16 by doubling (he tube diameter. 

The volume flow rate and the pumping power requirements are... 

Consider the flow of oil at 20°C in a 30-cm-diameter pipeline at an average velocity of 2 m/s (Fig. 8-24). A 200-m long section of the horizontal pipeline passes through icy waters of a lake at 0°C. Measurements indicate that the surface temperature of the pipe Is very nearly 0°C. Disregarding the thermal resistance of the pipe material, determine (a) the temperature of the oil when the pipe leaves the lake, (b) the rate of heat transfer from the oil, and (c) the pumping power required to overcome the pressure losses and to maintain the flow of the oil in,the pipe. 

SOLUTION The flow rate through a specified water tube is given. The pressure drop and the pumping power requirements are to be determined. 

C How is lire friction factor for flow in a lube related to the pres.sure drop How is the pressure drop related to the pumping power requirement for a given mass flow rate ... 

Water at 15 C is heated by passing it through 2-cm-inlemal-diametcr thin-walled copper tubes. Heat is supplied to the water by steam that condenses outside the copper tubes at 120 C. If water is to be healed to 65°C at a rate of 0.2 kg/s, detennine (a) the length of the copper tube that needs to be used and (b) the pumping power required to nvercomc pressure losses. Assume the entire copper tube to be at the steam temperature ofI20 C. 

Engine oil flows in a 15-cm-diameler horizontal lube with a velocity of 1.3 m/s, experiencing a pressure drop of 12 kPa. The pumping power requirement to overcome this pressure drop is... 

C What is the role of the baffles in a sheli-and-tubo heat exchanger How does the presence of baffles affect the heat transfer and the pumping power requirements Explain. 

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