Experimental and Numerical Analysis of a Thermodynamic Control System for Cryogenic Propellant Storage
Abstract
A technological barrier for long duration space mission using cryogenic propulsion is the control of
propellant tank self-pressurization. Since the liquid propellant submitted to solar fluxes tends to vaporize,
the pressure rise must be controlled to prevent mission failure. The Thermodynamic Vent System (TVS)
is such a control strategy: liquid propellant pumped from the tank, is cooled down by a heat exchanger
and re-injected as a sub-cooled spray inside the tank. The tank pressure drops due to vapor condensation
and liquid bath destratification (Refs. 1 to 4). Our research strategy combines an on-ground experimental
set up (Ref. 5) and Volume of Fluid (VOF)-based simulations. The cylindrically-shaped tank is filled with
a surrogate fluid (Novec1230 by 3M). The thermal input is controlled by an electrical heating coil. An
original insulation technique is used to prevent undesirable heat flux from the wall. The double shroud is
thermalized by a water loop, regulated to follow the average tank temperature variation. Injection
temperature and mass flow rate are fixed during an experiment. Instrumentation gives access to the
accurate measurement of the tank vertical temperature distribution and allows to assess the TVS
efficiency. To optimize the TVS design, the experiment will be numerically reproduced using an in-house
solver based on VOF approach for interface tracking (Ref. 6), and a phase change model taking advantage
of a sharp mass transfer rate distribution (Ref. 7). Experimental results, including thermal stratification
quantification in the tank will be presented for various heat loads and TVS control parameters.
Preliminary numerical results demonstrating the accuracy of the developed solver will be also provided.