The purpose of this project was to calculate the dimensions of a centrifugal pump, for a determined application, to write a report and then to make an oral presentation, in English, to an auditorium. Therefore, this is a complete project from the choice of the specifications with documented research to the design of the pump. The first thing was to define the field of application and the specifications of the pump: water flow, engine rotation speed and characteristics of ducts before and after the pump. The entire pump installation has to be studied in order to calculate the total pressure drop in the system: length, radius and roughness of ducts, the eventual presence of elbows which increase local pressure drop, etc. We then use, for the calculation of the characteristics, an Excel software which is very simple to use and efficient. The second aspect was to work in groups, to divide the tasks into different parts. Then, at the end of the project, take stock of the situation and to compare our work with our initial aim.
[...] For instance, current values of pressure are around 10 to 20 atm (150- 250 psi) and with a flow rate around 200 to 400 m3/h l/s). The system is composed in two parts : a removable and a fixed part. The fixed installation is the centrifugal pump near the water source and the removable part is the sprinkler and ducts. an ANSIMAG centrifugal pump Pump location What is expected : Canal characteristics Ducts characteristics Pump characteristics Part two : the theory Phenomenons to avoid Cavitation. The formation and subsequent collapse of vapor-filled cavities in a liquid due to dynamic action is called cavitation. [...]
[...] A brief conclusion will end this report. The last page sum up data about the fluid, ducts, the pump . Part one : Presentation Pump operating principle General information. Pumps are used to add energy to the fluid. Fluid machines can be divided into two main categories : positive displacement machines (denoted as the static type) and turbo-machines (denoted as the dynamic type). Positive displacement machines force a fluid into or out of a chamber by changing the volume of the chamber. [...]
[...] Rotation of the rotor produces dynamic effects that either add energy to the fluid or remove energy from the fluid. Examples of turbo-machines-type pumps include propellers on ships or airplanes, axial-flow water pumps used in deep wells Operating principle. The centrifugal pump is one of the most common radial-flow turbo- machines. This type of pump has two main components : an impeller attached to a rotating shaft, and a stationary casing or volute enclosing the impeller. The impeller consists of a number of blades, usually curved, arranged in a regular pattern around the shaft. Illustration . [...]
[...] Hth( : Hth : At the beginning, p was fixed to 0,3 but its real value (calculated with the Pfleiderer formula) is 0,143. jc is the pressure drop due to impact of the fluid on the wheel : jc = Va with jf is the pressure drop due to the friction : Jf = with = 6816,6 Then this formula will give us Hu : Hu = Hth jf jc = Hth - - Va Then Hu = Hth jf jc Part three : results Graphs The following graph is a summary of the different characteristics of the pump in function of the water flow. [...]
[...] The efficiency begins at 0,72 increases to 0,9 (for V = 0,04 m3/s) but decreases quickly to 0 = 0,085 m3/s). This board sums up the pump with some specific points : Pump selection, comparison with industry Searches on the web give us interesting information. The following graph of ANSIMAG company regroups a lot of pump but there is no pump with a such flow (200 m3/h). But an another serial number is specialised in large water flow 100 m3/h). The two following type of pump have characteristics we search. [...]
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