A thermal model of the conical evaporator in Pluto/Express, multi-tube AMTEC cells

A detailed thermal model of the conical evaporator of Pluto/Express AMTEC cells is developed to evaluate the effect of evaporator cone angle (between 0 degrees and 90 degrees) on the cell performance and temperature margin. The model calculates the effect of the cone angle on the vapor exit temperature and mass flow rate as a function of the cell design, operating hot side and condenser temperatures, external load resistance, and the design and type of the structure materials of the evaporator standoff. This paper describes the evaporator thermal model, and the numerical approach and method of solution used. Results were not available at the time of publication, but will be presented at the conference.