BACKGROUND
Centrifugal pump is a type of hydraulic machines that uses centrifugal force for converting the mechanical energy into pressure energy. This pump works in the reverse direction of an inward radial flow reaction turbine on the principle of the forced vortex flow. This principle states that whenever an inevitable rise in liquid mass is related by an external torque, there will be a rise in the pressure head of the rotating liquid. This rise of the pressure head at any point of the rotating fluid is directly proportional to the square of the tangential velocity. Centrifugal pump has typically higher flow rates and comparatively constant discharge than positive displacement pumps (PDs).1
The important parts of the centrifugal pump are the impeller, casing, suction pipe with a foot valve and filter, and a delivery pipe. An impeller is a rotating part which has a series of backward curved vanes. Impeller has a similar type of casing of a reaction turbine which has an air-tight passage. This casing converts the outlet discharged water’s kinetic energy to the pressure energy before leaving it.2 This conversion occurs due to the unique design of housing of the centrifugal pump. The one end of the suction’s pipe is connected to the pump’s inlet while the other’s end is dipped into water in a sump. Contrary to this, the one end of the delivery pipe is connected to the pump’s outlet, and the other end delivers water to the required height.3 The main set up of this experiment consists of the parts of the electrical driving unit along with the centrifugal pump.
The sole objective of this experiment is to study the performance of a centrifugal pump.
REQUIREMENTS
Materials: Centrifugal pump with driving unit
Pressure gauges
Stopwatch
Collecting Tank
Pressure Gauges
Metre Scale
PROCEDURE
First of all, measure the internal plan dimension of collecting tank and the suction and pressure gauge level difference. Now, note down the pump speed and its energy meter reading. By fully opening the delivery pipe, start the driving unit. After this, with the help of the suction pipe, the water is sucked, and it is lifted with the help of a centrifugal action of the pump. After this, take readings for different delivery head and discharge which can be varied by varying the pressure gauges. Calculate the readings for vacuum gauge, pressure gauge, time taken for energy meter disc revolution, and time taken for the rise in the collecting tank while the outlet valve is closed.
CONCLUSION
The study of the performance of the centrifugal pump has been discussed. No pumps are ‘ideal’, and their performances are determined by the manufacturer. The best driving condition for the pump is obtained in corresponding to the maximum efficiency.
REFERENCES
- L. W. Z. H. Z. L. Z. B. Dazhuan Wu, “Experimental study on hydrodynamic performance of a cavitating centrifugal pump during transient operation,” Journal of Mechanical Science and Technology, vol. 24, no. 2, pp. 575-582, 2010.
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R. F.-P. J. L. R. M. H. a. B. S. O. Coutier-Delgosha, “Experimental and Numerical Studies in a Centrifugal Pump With Two-Dimensional Curved Blades in Cavitating Condition,” Journal of Fluids Engineering, vol. 125, no. 6, pp. 970-978, 2004.
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J. A.-T. R. Spence, “A CFD parametric study of geometrical variations on the pressure pulsations and performance characteristics of a centrifugal pump,” Computers & Fluids, vol. 38, no. 6, pp. 1243-1257, 2009.
