Characteristic of a multistage reheating radial inflow in supercritical compressed air energy storage with variable operating parameters

Abstract

In the present study, aerodynamic performance of a four-stage reheating radial inflow turbine, which is adopted in the 1.5 MW supercritical compressed air energy storage system, is analyzed by using the method of integral numerical calculation. Results illustrate that when the inlet total pressure of the first stage is decreased, the expansion ratio of the fourth stage decreases the most. System isentropic efficiency decreases about 1% when the inlet total pressure of the first stage is changed from 7 MPa to 3 MPa, and the fourth stage's isentropic efficiency decreases about 7%. When the rotational speed is decreased, isentropic efficiency and total power decrease gradually and isentropic efficiency changes from 90.5% at 110% speed ratio to 71.1% at 60% speed ratio. Increasing reheating temperature results to the decrease of mass flow rate and isentropic efficiency and the increase of total power. Total power increases by about 105% when the reheating temperature is changed from 60 C to 520 C. When the guide vane opening of the first stage is increased, the expansion ratio of the first stage shows different trends compared to other stages and mass flow rates, and total power are proportional to the guide vane opening. System isentropic efficiency decreases by about 4% when the guide vane opening is adjusted from 80% to 30%.

Leakage flow characteristic of radial inflow turbine adopted in CAES system: Review on progress

“…However, it is difficult to adopt one stage radial inflow turbine to achieve high efficient power output with the expand ratio more than 70, therefore, a multistage radial inflow turbine is proposed and adopted. 13 As shown in Figure 3, every two radial inflow turbines are connected with one rotational axis, and these radial inflow turbines are further integrated with a gear box to form a multistage radial turbine to complete the power output. Each radial turbine is connected with pipes, and four heat exchangers are employed to recovery the compression heat by increasing the inlet temperature of the radial inflow turbines.…”