Throughout the world, water turbines have been used in the generation of power. This happens when water that is under pressure strikes the turbine vane thus producing mechanical work. The force that is generated gives out rotational motion when the jet hits the vanes. A clear example of a water turbine is the Pelton wheel. This form of a turbine has more than one water jets which are normally tangentially directed towards vanes which are tightened on the turbine disc rim. The water creates an impact on the vanes producing a torque on the wheel. The torque makes the wheel to rotate thus developing power. The prediction of the pelton wheel’s output and determination of the optimum speed of rotation requires the understanding of the jet’s deflection to produce a force at the bucket and its relation to the momentum rate of the jet. This experiment explores the various forces that are exerted by a water jet on different plates. In this experiment, the measurement of the generated force when a water jet strikes a deflector was obtained.
Whenever a horizontal water jet with a velocity v1 hits a freely moving plate, a force would be generated to the plate through the jet’s impact. This force, according to the theory of momentum is equal to the needed force in bringing back the plate in the initial position. This force should be same as the rate of momentum change of the flowing water towards that direction. In this regard, when F is a force of balancing needed to return the plate to the original position, it means that;
F = ρ Ǫ (v1-v2), where V2 includes the velocity of the jet in the direction that is horizontal after hitting the plate, V2 is certainly zero. This implies that
F = ρ Ǫ v1F = ? O v1 F= , where is the jet’s cross-sectional area. The calculation of the force due to the jets impact on a plate requires the application of the momentum change principle. According to this principle, the force produced is equivalent to the rate of momentum change. This is given by the equation that described. Additionally, the volume of the rate of flow in the above equation could be calculated in the experiment by calculating the quantity of the volume in a specific time period. Thos equation would be given by; Q=v/t. V1 could be calculated in the experiment through identifying the nozzle velocity and making use of the equations of motion. V2, on the other hand, could be obtained by measuring the nozzle’s diameter and making use of the equation of motion. Therefore, Vnozzel= Q/A. V1 could be calculated using; V12 = Vnozzel2-2gs where by g represents acceleration due to gravity, S represents the distance in between the plates and the jet. From these calculations, the force for the hemispherical cup is F = 2 ? O v1. For the flat plate, F = ? O v1. Apparatus. In this experiment, the following apparatus were used; hydraulic bench, water jet apparatus, loading weight, stopwatch, weighing tank, and deflectors like the hemisphere, plate, and slope. Experiment procedures. In this experimental set up, the procedure was as follow. The flat plate was fitted on the apparatus. After fitting the cup, water was removed from the cup through undoing the retaining screw and lifting it out. This is completed using the loose cover plate. The cover plate was fitted over the flit plate stem while holding it in position under the beam. Then, the retaining screw was screwed and tightened. It was then that the weigh-beam was set