Preliminary Design and Off-Design Analysis of a Radial Outflow Turbine for Organic Rankine Cycles

Abstract

Recently, the advantages of radial outflow turbines have been outstanding in various operating conditions of the organic Rankine cycle. However, there are only a few studies of such turbines, and information on the design procedure is insufficient. The main purpose of this study is to provide more detailed information on the design methodology of the turbine. In this paper, a preliminary design program of a radial outflow turbine for organic Rankine cycles was developed. The program determines the main specifications of the turbine through iterative calculations using the enthalpy loss model and deviation angle model. For reliability evaluation of the developed algorithm, a 400.0 kW turbine for R143a was designed. The designed turbine was validated through computational fluid dynamics. As a result, the accuracy of the program was about 95% based on the turbine power, which shows that it is reliable. In addition, the turbine target performance could be achieved by fine-tuning the blade angle of the nozzle exit. In addition, performance evaluation of the turbine against off-design conditions was performed. Ranges of velocity ratio, loading coefficient, and flow coefficient that can expect high efficiency were proposed through the off-design analysis of the turbine.

Design and Optimization of a Radial Turbine to Be Used in a Rankine Cycle Operating with an OTEC System

“…Q 3 was estimated using the value of ρ 3 based on exit condition with the help of REFPROP using a known value of mass flow rate. The value of ∆h s was taken from Equation (16).…”

“…In this context, Zheng et al [15] conducted a design and optimization study based on meanline design calculations. Kim and Kim [16] performed a preliminary design study for a radial inflow turbine based on one-dimensional calculations. They have adopted new techniques of loading coefficients to achieve a design with higher efficiency.…”

“…However, the optimization procedure for the turbine design parameters is missing in the literature for small scale ORC turbines. To fill the gap, the current study was conducted to design and optimize the turbine for the same conditions and working fluid (R152a), as used by Kim and Kim [16]. For the design and optimization process, a MATLAB code was developed which was linked with the NIST REFPROP [17] to access the properties of the working fluid at various states.…”

Multipoint Design Optimization of a Radial-Outflow Turbine for Kalina Cycle System Considering Flexible Operating Conditions and Variable Ammonia-Water Mass Fraction

“…Both features enhance the corrosion resistance of a radial-outflow turbine and make it well-suited for the Kalina cycle-based energy recovery system. Due to such features, the radial-outflow turbine has been commercially applied regarding the recovery of geothermal energy [11][12][13], supercritical CO 2 power cycle [14][15][16], and Organic Rankine Cycle (ORC) applications [17][18][19][20].…”

Preliminary Design of an Axial-Flow Turbine for Small-Scale Supercritical Organic Rankine Cycle

“…Based on a 150 • C heat Energies 2021, 14, 5277 2 of 20 source, Fiaschi et al [16] designed a 50 kW radial-flow turbine, and the incident angle of the rotor blade maintained positive to increase the load and improve the compactness. In addition, the radial outflow turbine had been proposed [17]. However, for the design of radial turbines with a high pressure ratio and a small mass flow, the gap between rotor blades is very small, which is a huge challenge in the actual engineering manufacturing.…”