Performance of Pelton Turbine for Hydroelectric Generation in Varying Design Parameters
Water power is a renewable energy source which has great potential in replacing fossil energy for generating electricity. The aim of this research is to analyze the influence of vertical distance of water source (water head) and nozzle diameter on the electrical power generated by Pelton turbine. It used Pelton turbine type with 22 buckets (vanes) which employed a PMG 200 watts generator with 1 : 2 pulley transmission system. Four different values of nozzle diameter and three different values of water head were chosen as the design parameters of the turbine. The electrical power was measured in three replications for each combination of the design parameters. The research showed that water head and nozzle diameter significantly affect the power generated by the Pelton turbine. The higher the water head from the surface, the more power generated. It was found that the electric power linearly increases with the increasing of nozzle diameter. However, it reaches the peak in 9 mm nozzle diameter and is getting lower in a larger diameter. The highest electric power of 16.89 watt is observed by adjusting the water head on 4.6 m with 9 mm nozzle diameter. Those design parameters are able can produce a rotation speed at 320 rpm in the generator. By identifying the appropriate parameters, it is possible to have more power generated by the water turbine used for hydroelectric power generation plant.
Pengaruh Ukuran Diameter Nozzle 7 Dan 9 MM Terhadap Putaran Sudu Dan Daya Listrik Pada Turbin Pelton
ABSTRAKSI Dalam perancangan sudu Turbin Pelton ini adalah untuk dapat mengetahui daya yang dihasilkan oleh putaran poros sudu yang di sambung dengan alternator sebagai penghasil arus listrik. Untuk putaran maksimal yang dapat dihasilkan oleh sudu Turbin Pelton ini adalah menggunakan nozzle 9 mm dengan putaran sebesar 1267 dengan bukaan katup maksimum 90 0 . Sedangkan debit aliran fluida yang didapat yaitu pada kombinasi kedua nozzle yaitu pada nozzle 7 dan nozzle 9 yang menghasilkan 0,00097 m 3 /s. Kecepatan aliran fluida terbesar dihasilkan terdapat pada nozzle 7 dengan bukaan katup 90 0 dengan hasil 0,52 m/s. Dan daya yang dapat dihasilkan oleh alternator memperoleh hasil 3,53 dengan menggunakan kedua buah nozzle dengan bukaan pada 65 0 . Putaran turbin Pelton sangat dipengaruhi oleh nozzle yang digunakan, bukaan katup dan tekanan pada pompa yang berfungsi mengalirkan fluida.
Prediction of a representative point for rail temperature measurement by considering longitudinal deformation
Monitoring rail temperature is very important for determining the safe running speed of trains and to prevent buckling. In general, the maximum variation of the internal rail temperature can be >7 ℃ depending on the point of measurement. However, there is as yet no sufficient information about how to predict the measurement point to represent the thermal deformation due to temperature distribution. In this study, the authors report a new point, called the representative measurement point, at which the rail temperature can be measured. This point considers the average deformation of the rail through structural analysis by adopting experimental and actual rail temperature data. The authors designed and installed a measurement system similar to an actual rail environment. Using the system, various data were acquired (internal/surface rail temperature and weather data) for 10 months. On the basis of these data, an analysis was done to calculate the average deformation point through thermal analysis. Finally, the representative measurement point was proposed as the position at which the average deformation point converges regardless of weather or seasons. The authors believe that the method described herein is advantageous in that it could be used in a high-accuracy temperature-monitoring system and for predicting thermal deformation and buckling.