Experimental investigation of CO2 dry-ice assisted jet impingement cooling

The novel concept of dry-ice assisted jet impingement cooling is proposed in this study. When carbon-dioxide (CO2) passes through a tiny orifice gap or jet nozzle, it experiences a rapid temperature drop as well as a pressure decrease via the Joule-Thomson effect. This temperature drop causes the formation of small CO2 dry-ice particles. In addition to the enhanced cooling performance caused by lowered bulk-jet temperature, heat transfer is improved by the additional sublimation effect between the dry-ice particles and the cooling target surface. A comparison of the cooling performance between the suggested CO2 solid-gas two-phase jet and a single-phase nitrogen (N2) jet was performed experimentally. In the experiment, both jet fluids are expanded through a circular nozzle and impinged on an electrically heated flat heater surface, and their heat transfer coefficients are measured. The performances of the impinging jet for both fluids are also evaluated via the variance of flow parameters, for example, the Reynolds number, and the jet geometry configurations.