What is specific speed in pump?

The specific speed (ns) is a characteristic coefficient derived from the similarity conditions which allows a comparison of impellers of various pump sizes even when their operating data differ (flow rate and head at best efficiency point, rotational speed).

What is specific speed in centrifugal pump?

Specific speed is an index used to predict desired pump or turbine performance. i.e. it predicts the general shape of a pump’s impeller. It is this impeller’s “shape” that predicts its flow and head characteristics so that the designer can then select a pump or turbine most appropriate for a particular application.

What is specific speed and what is its effect on the pump curve?

Specific speed also affects head-capacity curve shape. Low specific speeds (500 to 1,500) produce flat curves. High speeds (6,000 and higher) produce steep curves. Intermediate speeds produce curves between the extremes.

What is specific speed of pump Quora?

Specific speed is defined as the speed in revolutions per minute at which a geometrically similar impeller would operate if it were of such a size as to deliver 1gpm flow against 1ft head.

What is the unit of specific speed?

Specific speed is the speed (in RPM) a geometrically similar impeller would need to operate in order to deliver 1 L/s of fluid at a head of 1 m (US units : 1 USgal/min at a head of 1 ft).

When the specific speed of the pump is 2600 the type of pump is?

centrifugal pump
Explanation: The specific speed of the pump is given by NS = NQ1/2 / H3/4 and when NS > 2600, the type of pump is centrifugal pump.

Why is specific speed also known as shape number?

In Europe, specific speed is sometimes called the “shape number,” and I prefer that name. It indicates the shapes of the performance curves and also determines, to a large degree, the profile shape of the impeller.

What is the minimum starting speed of centrifugal pump?

To get the minimum starting speed of a centrifugal pump, it is notice that if the pressure rise in the Impeller is more than or equal to manometric head (Hm) then the centrifugal pump will start to deliver water. Otherwise the pump will not discharge any water, the impeller is rotating.

Which of the following equation can be used for estimation of specific speed ns of centrifugal pump?

N s = N Q H m 3 / 4 Where NS = Specific speed, Q = Discharge, H = Head under which the pump is working, N = Speed at the pump is working.

What is NS and NSS in pump?

NS is an indicator of the impeller geometry and discharge characteristics, while NSS is an indicator of impeller inlet geometry and suction characteristics. NSS is, in essence, a function proportional to the speed, pump flow rate and the NPSHr.

Does MCSF vary with pump speed?

It is therefore possible that for a small number of pumps, the MSCF will not really change with reducing speed. However this generally only occurs on v low specific speed designs with low efficiences. For the vast majority of centrifugal pumps, the MCSF will reduce with reducing speed. Your boiler feed pump would fall into that majority.

What is specific speed?

Specific speed. Specific speed is an index used to predict desired pump or turbine performance. i.e. it predicts the general shape of a pumps impeller. It is this impeller’s “shape” that predicts its flow and head characteristics so that the designer can then select a pump or turbine most appropriate for a particular application.

What is suction specific speed?

A. Suction Specific Speed is an index that describes the characteristics of the suction side of the impeller. It is calculated using the NPSHr in feet, speed (N) in rpm, and flow rate (Q) in gpm at the pump’s Best Efficiency Point and maximum impeller diameter.

What is a two speed pool pump?

Two Speed Pool Pumps. The pool pump is the most important piece of equipment in your swimming pool system, but they’re also the greatest consumers of energy. But because two speed pool pumps are able to move your water at different speeds, this allows you to save a ton of energy and cut costs.