Calculation of characteristic curve of gear pump

Usually, the curve representing the relationship between the main performance parameters is called the performance curve or characteristic curve of the gear oil pump.

Essentially..

The performance curve of gear oil pump is the external manifestation of the movement law of liquid in the pump.

Obtained by actual measurement.

The characteristic curve of the gear oil pump is a group of curves plotted by the data of Q, H, N, η and so on which are measured experimentally.

This formula is provided by the manufacturer of stainless steel oil pumps..

For the use of the department to select the pump and operation reference.

The characteristic curve of different type pump is different..

But there are the following three curves H-Q line represents the relationship between the head and the flow

N-Q line represents the relationship between pump shaft power and flow η-Q line represents the relationship between pump efficiency and flow

The characteristic curves of the pump are measured at a certain speed..

Therefore, N value of rotational speed is noted on the characteristic curve.

The highest efficiency on the performance curve of the gear oil pump is called the design point..

The pump works most economically at the pressure head and flow rate corresponding to this point.

The performance parameters marked on the nameplate of the gear oil pump are the operating parameters at the highest efficiency point.

The performance curve of gear pump can be used as the basis for selecting pump.

After determining the type of pump..

And then according to the flow and pressure head pump selection.

The main performance parameters of a gear oil pump were measured with clean water.

The measured flow rate in the experiment is 10m3/h..

The pressure gauge at the pump outlet reads 0.17 Mpa gauge pressure..

The vacuum gauge at the inlet reads -0.021 MPa..

The shaft power is 1.07 kW..

The speed of the motor is 2900r/min..

The vertical distance between the pressure measuring point of the vacuum gauge and that of the pressure gauge is 0.2m.

Try to calculate the head and efficiency at the test point.

The main performance parameters of the pump include speed N, flow Q, head H, shaft power N and efficiency.

The parameter directly measured is the speed n=2900r/min..

Traffic Q10m3 / h = 0.00278 m3 / s..

Shaft power N  1.07 KW..

Need to calculate the head H and efficiency.

Use the formula H=h0+ p2-p1 /g to calculate the head H..

H0 = 0.5 m..

Rho = 1000 kg/m3..

The P2 / g = 1.7 * 1.73 * 9.81 = 105/1000 m..

P1 / rho g = - 104/1000 * 2.1 * 9.81 = 2.14 m..

So H = 0.5 + 17.3-2.14 = 20 m..

Ne = HQ rho g = 20 x 0.00278 * 1000 * 9.81 = 545 w = 0.545 kW..

Eta = Ne/N * 100% = 0.545/1.07 * 100% = 51%