Hydraulic efficiency of pumps

Hydraulic efficiency of pumps, 517 Hydraulic radius for fluid flow, 486 for heat transfer, 594-595 Hypalon, 435 HYSIM, 127... 

Since the exacd value of the hydraulic efficiency e, is never known, V/ can be taken as an approximation where e is the gross (hydraulic horsepower/brake horsepower) pump efficiency. Efficiencies of pump designs running as turbines are usually 5 to 10 efficiency points lower than those as pumps at the best efficiency point. 

The main purpose of recharging water into an aquifer is to elevate the hydraulic gradient to promote the movement of groundwater towards the collection system, thus enhance the efficiency of pumping. 

Compute the horsepower required to drive the pump. The brake horsepower input to a pump equals (gal/m i n)(Ht )(.v )/3960e, where s = specific gravity of the liquid handled, and e = hydraulic efficiency of the pump, expressed as a decimal. The usual hydraulic efficiency of a centrifugal pump is 60 to 80 percent reciprocating pumps, 55 to 90 percent rotary pumps, 50 to 90 percent. For each class of pump, the hydraulic efficiency decreases as the liquid viscosity increases. 

Assume that the hydraulic efficiency of the pump in this system is 70 percent and the speci fic gravity of the liquid handled is 1.0. Then, input brake horsepower equals (2000)(125)(1.0)/[3960(0.70)] = 90.2 hp (67.4 kW). 

GENERAL NOTE This Standard does not cover exact hydraulic performance of pumps. Information on approximate head and capacity at the best efficiency point for standard pumps is for general information only. Consult manufacturers regarding hydraulic performance data for specific applications. 

Viscosity must be taken in account when pumping viscous slurries. Viscosity reduces the efficiency of pumping and the head developed by a pump (Figure 8-43). The Hydraulic Institute Standards provides correction curves for viscous fluids pumping, but warns against extrapolating to other pumps or fluids. The Institute does not publish curves for viscous slurries. 

These motors have a lower efficiency as a result of running in liquid, causing more liquid drag and also axial thrust bearing loss, which is also a part of the motor. However, this lower efficiency of the motor is compensated by fewer mechanical and hydraulic losses in a submersible motor-pump installation, compared to a vertical turbine pump installation. 

Calculate the optimal hydraulic parameters for the hole depth of 8,555 ft if the available data are as given below Type of pump Continental Emsco F-1600 with 97% pump volumetric efficiency. To prevent rapid pump wear, the pump pressure should not exceed about 80% of the maximum pump pressure at any liner size. The hole size is 12- - in. and the mud weight is 9.7 Ib/gal. 

Figure 7.15. Effects of viscosity on performance of centrifugal pumps (a) Hydraulic Institute correction chart for pumping liquids, (b) Typical performances of pumps when handling viscous liquids. The dashed lines on the chart on the left refer to a water pump that has a peak efficiency at 750 gpm and 100 ft head on a liquid with viscosity 1000 SSU (220 CS) the factors relative to water are efficiency 64%, capacity 95% and head 89% that of water at 120% normal capacity (1.2QH).

That efficiency of HHP could be improved at use of the multistage modes, replacing hydrides (instead of one hydride) should have lower values of a heat capacity. Also it is necessary to remember, that the most systems suggested for triple heat pumps, more reduce, than expand areas, temperatures possible for double hydride systems. Thus hydraulic and gas hydrogen systems for installations with three hydrides considerably become complicated. 

This evaluation does not consider the advantage of the hermetical sealing, the system s safeguarding ability of the PDP and the fact that hydraulically actuated Diaphragm Pumps are saving energy due to their better overall energy efficiency. 

Another so-called efficiency, known as hydraulic efficiency, is sometimes given for reciprocating pumps. This efficiency indicates losses due to velocity changes in the inlet and outlet of the pump, friction, and valves. It is defined as the ratio of the actual head across the pump to the sum of the actual head pumped and the losses in the suction and discharge lines. 

Related Calculations. Use the method given here for any type of pump whose variables are included in the Hydraulic Institute curves (Figs. 6.10 and 6.11) and in similar curves available from the same source. Operating specific speed, computed as above, is sometimes plotted on the performance curve of a centrifugal pump so that the characteristics of the unit can be better understood. Type specific speed is the operating specific speed giving maximum efficiency for a given pump and is a number used... 

Hydraulic power transmission is used for slow-moving, powerful machinery requiring accurate control, or where load factors are very low. Efficiencies of hydraulic operation range up to 0.85, the chief loss being that due to the friction at cup leathers used for plunger packings. For direct steam pumps having the same number of fluid cylinders as steam cylinders, the ratio of areas of steam... 

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