twisted flow, high heat flux, critical heat flux, R404A
Devices for cooling high heat fluxes within small available spaces are called spot evaporators. Areas of application are for example the cooling of molds, power electronics or electrical mobility. The functionality of the spot evaporator bases on its geometry and is a combination of spray-cooling and pipe flow. Spray-cooling or jet impingement cooling is able to achieve high heat fluxes even at overcritical wall temperatures. To reach the same effects within the pipe-flow part of the spot evaporator, this part has to be twisted shaped. The paper focuses on the experimental analysis of the twisted shaped spot evaporator by varying fundamental parameters corresponding to the Model of Yagov. Two methods of generating the twist have been developed and compared to each other. The experimental results will be discussed. They show that the averaged critical heat flux can be raised up to 30 % compared to spot evaporators without twisted flow. As refrigerant R404A has been used.