c lithium slurry pumps

Lab #8 Ce336

Introduction:

To begin, the main idea behind this experiment is studying the dynamics of water flowing through a centrifugal pump at various speeds and comparing the results. The centrifugal flow is conducted under a parallel pump set up, and the reaction of the fluid flow is analyzed. A series of 5 trials was conducted, beginning at a motor speed of 50-Hz and then decreasing in 5-Hz increments until we had a motor speed of 30-Hz. We were then able to determine the efficiency of the pump at various speeds. A parallel pump configuration as well as a configuration of various sump valve settings was conducted both at a motor speed of 50 Hz. The pump converts electrical energy into head, and the reason we used a centrifugal pump in the experiment is because the liquid receives a big kinetic energy from rotation which is then released by centrifugal force. By comparing results such as different pump speeds effects on the head produces, flow rates with different power and efficiency, and inlet and outlet pipes affecting the total head produced, we were then able to gain a better understanding of centrifugal pumps.

Purpose of Study:

The objective of this experiment is to analyze characteristics of a centrifugal pump by measuring flow rate at various preset motor speeds, featuring a single pump as well as two pumps in parallel. Finally, we will calculate efficiency in order to fully un derstand the effects that the different settings had on the trials.

Theory:

First, it’s important to establish that a centrifugal pump takes rotational energy and converts that to an energy that it can use, hydrodynamic energy, which is the energy that is used to move fluids. Centrifugal action launches the fluid outwards as it enters the pump, and with many rotations we are able to have a high kinetic energy. The difference in velocity heads in the equipment that we used is negligible, as the diameters of the outlet and inlet are seen to be congruent. Because of this, we are able to take the equation:And rewrite it as:This is because the third term cancels out to be 0 since we established the difference in velocities are negligible. With this established, the pressure head recording is taken from the water meter at both outlet and inlet gauges located in the testing apparatus. The datum in the equation is located directly in line with the center of the pump impeller. This is also paired with a head correction factor in order to achieve a more accurate result:

Equipment:

●F1-27 app ara tus (Sc hem ati c i n f igu re 1)●Hyd rau lic B enc h F1-10 (Sc hem atic in fi gur e 1)●S t o p w a t c h

Set-Up &Procedures:

To start, we needed to ensure that the sump drain valve connected to the hydraulic bench was open, as well as making sure that the d ischarge control valve was closed. Turn on the inverter and press ‘run’, fix the motor speed to be 50-Hz (or extremely close to it). The power reading can be taken with the ‘FU NC/DATA’ button, and can b e read in either motor output (kW) or motor speed (Hz). After this, open the discharge valve and record outlet and inlet head as well as the time needed to accumulate 5L of water, which will be the data required in order to find the flow rate. Slightly close the control valve for the head change, and yet again record the data as previously done with the outlet and inlet heads. Vary the head by closing the discharge valve and just like before recording the head readings and the time needed to collect 5L of water. Close the discharge control valve completely for the data corresponding to no flow rate at all. This exact process is to be repeated 4 times, going down 5-Hz increments to 45-Hz, 40-Hz, 35-Hz, and finally 30-Hz. In the end, set the pump to 50Hz with the discharge control valve completely open and then take the readings after changing closing the sump drain valve in order to see suction loss in performance for the specific pump. For the parallel pump operation this time, close the control valve connected to the hydraulic bench whilst keeping the sump valve open. Also,close the discharge control valve and switch the pump in the hydraulic bench on. Next, open the control valve, turn on the F1-27 inverter, and preset the motor speed to around 50-Hz. Change the settings for the discharge control valve to completely closed and then take outlet and inlet head recordings. Low flow rates of less than 1.4 liters per second should be used to record time needed to fill 5 liters of water in the holding tanks, whereas anything above 1.4 liters per second with a high flow rate should be used to remove the sealing ball as well as the weight in the tank. Let the water level in the tank stabilize which may take a couple minutes before finally taking the value from the upper scale with the sight glass. This is done to find the actual flow rate.

Calculations:

Motor Speed (Hz) - Given Calculations for flow rate, total head, power output, and efficiency: