Jeon, Heungsu Park, Joo Hoon Shin, Youhwan Choi, Minsuk 2024-01-19T22:04:07Z 2024-01-19T22:04:07Z 2021-09-03 2018-08 0960-1481 https://pubs.kist.re.kr/handle/201004/121108 This study is dedicated to find a cause of a critical flow rate in a Pelton turbine operating with a constant runner speed, below which the efficiency of the turbine decreases significantly. A critical flow rate was initially found in the performance test of the Pelton turbine for extracting energy from a PRO (pressure retarded osmosis) pilot plant. For higher flow rates than a critical value, the efficiency of the Pelton turbine was nearly constant independent of flow rates. For lower flow rates than a critical value, however, the efficiency drops with decreasing flow rates. 3D flow simulations were conducted at three different flow rates to investigate effects of flow rates on the performance of the Pelton turbine. It was found in the numerical results that a large friction loss is generated in an injector if the spear is closed too tightly for a low flow rate below a critical value. Head loss coefficients of the injector for three different spear positions were calculated and it was found that the loss is doubled below a critical flow rate. This implies that it is important to include the geometry of an injector and spear in the numerical simulations for Pelton turbines. (C) 2018 Elsevier Ltd. All rights reserved. English PERGAMON-ELSEVIER SCIENCE LTD NUMERICAL-SIMULATION FLOW-ANALYSIS JET BUCKET CFD Friction loss and energy recovery of a Pelton turbine for different spear positions Article 10.1016/j.renene.2018.02.038 1 RENEWABLE ENERGY, v.123, pp.273 - 280 RENEWABLE ENERGY 123 273 280 scie scopus 000430769100024 2-s2.0-85042285831 Green & Sustainable Science & Technology Energy & Fuels Science & Technology - Other Topics Energy & Fuels Article NUMERICAL-SIMULATION FLOW-ANALYSIS JET BUCKET CFD Pelton turbine Injector Friction loss Head loss coefficient PRO