thermal lab

Group 1

ME 495

09/12/16

Lab 1: Pelton Turbine Extended Abstract

In this experiment, our team will observe a flow through a Pelton Wheel and be able to calculate the input and output power. Our team is tasked with comparing the efficiency of the turbine, using readings taken at the nozzle inlet, with the theoretical efficiency. The theory behind this experiment is that a change in momentum of an object must have an impact force acting upon it. The Pelton Wheel uses a jet stream, with some input power, which strikes a bucket causing the the wheel to rotate creating a torque. This torque in turn creates an output power. The theoretical calculations assume that the the nozzle cross section is constant, the fluid is incompressible, the fluid is under constant pressure, and the velocity of the fluid is constant. It is expected that the theoretical values and the experimental values should be the same, or very close to each other. If they are not then some of the assumptions used in calculating the theoretical values are incorrect or over simplistic.

The measurement devices that will be used for this experiment are a stopwatch, a stroboscope, pelton wheel, and a hydraulic bench. The stopwatch, a phone will most likely be used, measures time and has a resolution of 0.01 seconds. The stroboscope will measure the rpm of the wheel, most stroboscopes have a resolution of 1 rpm. The pelton wheel setup will measure the torque created by the forced rotation, which can can be translated into an output power. Lastly, the hydraulic bench regulates the flow rate, Q, the uncertainty for the bench is 0.5L.

Turbine efficiencies are a very useful knowledge especially in the power industries mainly those who operate power plants that rely on a cooling system such as a nuclear power plant. The turbines are part of a larger mechanism that functions to cool down the water that flows throughout the plant. The larger the efficiency of the turbine the less power that plant will have to use to run this cooling system. Scrubbers also rely on turbines to bring polluted air in for the scrubbers to clean. Though turbine efficiency is not as big of a concern than that in the power plant it does play a significant role in the efficiency of the main scrubbers.