An experimental investigation of transpiration cooling characteristics with phase change of liquid water was carried out.The specimen used in the experiments was made of porous materials sintered by refractory steel powder.The surface temperature of the specimen was measured by an infrared thermal imaging system.The variety of pressure and temperature in coolant chamber detected by the thermocouples and pressure sensor were used to analyze the phase change process of cooling water.The results indicate that average cooling efficiency is improved gradually with the increase of cooling water injection rate;but when liquid vapor phase change happens on the specimen surface exposed in hot gas

average cooling efficiency tends gradually to be stable;main flow temperature and cooling water injection rate determine the phase change position of cooling water

thus affecting pressure variation in the coolant chamber.