Radial turbine is the core component of organic Rankine cycle(ORC) system with high efficiency and simple structure

its performance directly affects the heat-to-power conversion efficiency of the system. In the waste heat recovery(WHR) system of internal-combustion engine(ICE)

the working state of turbine is affected by the complex and changeable working conditions of the ICE

so it's necessary to analyze the overall performance of turbine and explore the characteristics of working conditions boundary. However

the previous work has focused on the performance research near the design conditions. The computational hydrodynamic software is used to carry out numerical simulation and performance analysis for centripetal turbine under full load condition. The result shows that

the output power and efficiency under design condition are 13.435 kW and 79.31%. For off-design conditions

the temperature variation has a small effect on turbine performance. The inlet pressure affects the output power by changing mass flow rate

and the relationship is linear

when the inlet pressure is 50% design value

the efficiency changes dramatically under the influence of rotation speed

it's hard to work steadily. The rotation speed has a great influence on the working state of turbine

when the speed changes in the range of ±40%

the efficiency is above 60% and the peak value is close to 80%. When the speed changes out of ±50%

the efficiency drops sharply or even approaches 0

at which condition the turbine is not suitable for operation. The results can provide reference for design and operation of ORC radial turbines.