Measure the head of a gear oil pump

We want to measure the head of a gear oil pump.

The liquid is 20℃ oil..

When the measured flow is 590m/h...

Pump inlet vacuum gauge reading is -0.03MPa..

The outlet pressure gauge reads 0.48 MPa (gauge pressure)..

It is known that the vertical distance between the two tables is 0.45m. If the suction pipe of the pump is the same as the pressure pipe diameter...

Try to calculate the head of the pump.

U The solution is given by the equation H=h0+ p2-p1 /ρg..

Look up 20 ℃..

Rho = 998.2 kg/m3

The reading of the pressure gauge at the pump outlet (Pa) P1 is the reading of the vacuum gauge at the pump inlet (negative gauge pressure value...

Pa).

Head is the amount of energy per unit weight of fluid that is pumped.

The Bernoulli equation between two sections in a pipeline system (including pump) is listed and arranged. It can be obtained that H=△Z+△ P ÷ρ G +△ U2 ÷ρ G +∑ H1-2, where H is head..

The lifting height only refers to Δz.

H = 0.45 mp = 0.47 Mpa = 4.7 * 105 pap = 0.02 Mpa = 2 * 104 pa

H = 105 + 0.45 + 4.7 * 2 * 9.81/104/998.2 = 50.5 m

3. Speed n Speed is the number of revolutions per unit time of pump shaft..

Use the symbol N to indicate...

The unit is the r/min

4. NPSH

A. When the pump is working, the liquid at the inlet of the impeller will produce vapor under a certain vacuum pressure.

The vaporized bubbles are impacted by the liquid particles...

The metal surface such as impeller is denudated..

So as to destroy the impeller and other metals..

At this point the vacuum pressure is called vaporization pressure.

B. Np allowance is also called net positive suction head..

Is the main parameter of cavitation performance.

Napitation allowance refers to the excess energy of the liquid per unit weight at the pump inlet that exceeds the vaporization pressure.

Units are marked in meters..

Use the NPSHr.

C. Suction is the necessary NPA Δ H pump is allowed to suck liquid vacuum degree..

The allowable installation height of the pump...

The units are meters.