Design and performance analysis of radial-inflow turboexpander for OTEC application

摘要

Ocean thermal energy conversion (OTEC)is a potential source of renewable energy. In order to design a turbine for maximizing the output power for very low working temperature application like OTEC, careful one-dimensional design followed by detailed three dimensional simulation is required. In this work a radial-inflow turbine with R-22 as working fluid is designed for a closed-cycle ocean thermal energy conversion plant of 2 kWe capacity. Design speed of the turbine is 34000 rpm. Inlet and outlet temperatures of designed turbine are 24.5 degrees C and 14 degrees C respectively. Three-dimensional fluid flow analysis inside the turbine at design and off-design conditions were carried out. Important dimensions of the turbine are: rotor tip and shroud radii of 24 mm and 19 mm respectively; blade widths at rotor inlet and outlet of 6 mm and 11 mm respectively; axial length of 17.5 mm; diffuser of 62 mm long. Volute casing designed has a circular cross section. The importance of the number of blades, blade filleting and stagger angle from the point of view of turbine performance are reported. (c) 2015 Elsevier Ltd. All rights reserved.