This paper describes the results of Engineering Development Unit (EDU) testing of a graded-groove Variable Conductance Heat Pipe (VCHP). This EDU pipe contains all the essential design features of an end-item unit, including multiple bends, flex sections, stainless steel transport section and high heat flux evaporator.
Testing covered a wide range of environments including hot and cold condenser temperatures, hot and cold reservoir sink temperatures, and varying evaporator powers.
A control algorithm was also developed which was designed to minimize warm-up time of the evaporator, minimize overshoot of the evaporator temperature, and maintain a stable evaporator temperature after warm-up.
Testing was performed to determine whether the VCHP reservoir needed to be cooled during testing in an ambient environment. Results of the model correlation are also presented.