Describe about the Chemical Engineering Lab For the Centrifugal Pumps.
Pumps are mechanical devices that are used for raising, compressing and moving a fluid and are largely used for performing different chemical engineering activities that help make work easier. This is a laboratory activity that is aimed at performing a characterization of a centrifugal pumps as well as evaluating the effects of connecting pumps in both parallel and series. (Derakhshan & Nourbakhsh, 2014).
The main objectives of carrying out this laboratory exercise was to;
- To perform a characterisation the centrifugal pump performance over a range of rates of flow.
- To find out the lines of equal power and efficiency and make a presentation of these lines by plotting graphs that represent the information
- To characterise the performance of the pumps when the connection of centrifugal pumps are done in both parallel and in series.
Results and discussion
- Pump characteristics
The experiment was mainly focused on determining the operating characteristics of the centrifugal pump. The major graphical representations of the performance of a pump that will be measured in this experiment are;
- Pump efficiency, E
- Power input to the pump, Pm
- Change in total head produced by the pump, Ht
- Pump characteristic curves
The experiment was categorized into two. It first begins by determining the characteristic curves for a single pump where we determine graphical representations of the Pump efficiency, Power input to the pump and the Change in total head produced by the pump. Next was to determine the characteristic curves for pumps connected in parallel and in series and then the same procedure for a single pump followed (Moreno et al, 2012).
Characteristic curves for Pumps in series and parallel
Each of the parameters, pump efficiency, total head and power input, are measured at some pump speed that is constant. A graphical representation is carried out to show the performance of each of the parameters. From the presentation, we can be able to determine the overall performance of the pump.
The head and flow rate curves represents the relationship that exists between the rate of flow and the total head. They are represented by an Ht-Q curve. It can be seen that as the rate of flow increases, the total also decreases. This represents a rising characteristic type of curve. For this experiment, there was only a single possible rate of flow for a given head, representing a stable head-capacity characteristic type of curve (Muggli, Holbein & Dupont, 2015).
From the experiment, we can realize that the three major characteristics of the pump, the Pump efficiency, Power input to the pump and the Change in total head can be defined using different levels of speed for the pump. This experimental activity therefore achieves the objective of determining the pump characteristics of a centrifugal pump. The experiment is also useful when determining different parameters of the pump that are required (Nautiyal et al, 2011).
Derakhshan, S., & Nourbakhsh, A. (2014). Experimental study of characteristic curves of centrifugal pumps working as turbines in different specific speeds. Experimental thermal and fluid science, 32(3), 800-807.
Moreno, M. A., Planells, P., Córcoles, J. I., Tarjuelo, J. M., & Carrión, P. A. (2012). Development of a new methodology to obtain the characteristic pump curves that minimize the total cost at pumping stations. Biosystems Engineering, 102(1), 95-105.
Muggli, F. A., Holbein, P., & Dupont, P. (2015). CFD calculation of a mixed flow pump characteristic from shutoff to maximum flow. Journal of fluids engineering, 124(3), 798-802.
Nautiyal, H., Varun, V., Kumar, A., & Yadav, S. Y. S. (2011). Experimental investigation of centrifugal pump working as turbine for small hydropower systems. Energy Science and technology, 1(1), 79-86.