Development and research of loop heat pipes with flat evaporators

The results of the development and testing of copper-water loop heat pipes with flat-oval and flat disk-shaped evaporators are presented. The active zones of the evaporators are $27$ and $26.5$ cm$^2$, respectively. The devices were tested in a horizontal position with a heat source having a heating surface of $16$ cm$^2$. A flat flow heat exchanger was used as a heat sink, through which water was pumped at a temperature of $40^{\circ}$C. At a maximum heat load of $900$ W, loop heat pipes with a flat-oval evaporator showed a thermal resistance of $0.036^{\circ}$C/W. For loop heat pipes with a disk-shaped evaporator, these values were $800$ W and $0.054^{\circ}$C/W, respectively. The devices can be effectively used in cooling systems for objects with a heating surface up to $30$ cm$^2$, dissipating up to $230$–$520$ W at a maximum temperature of $70$–$90^{\circ}$C. Examples of the use of loop heat pipes in such systems are presented.