Simulation of Rocket-Grade Kerosene Flowing in an Electrically Heated Experimental Apparatus.

摘要

A model is developed of the steady three-dimensional combined flow of fluid, heat and electricity in an experimental apparatus designed to test fuel thermal stability. A numerical simulation is performed for the purposes of model validation and assessment of the detailed thermal characteristics of the apparatus. Conjugate heat transfer and electric current flow of rocket-grade kerosene (RP-2) flowing in an electrically heated tube is simulated. The model and boundary conditions are selected so as to simulate an experimental case reported in the fuel thermal stability literature. The model includes steady, incompressible, variable-density turbulent flow inside the tube, thermally coupled with steady heat conduction, and electric current flow in the solid copper apparatus. Temperature dependence of fluid and solid thermodynamic and transport properties is included in the model. The tube inner wall surface roughness is adjusted in order to match the cooling efficacy of the fuel in the simulation with that observed in the experiment. The simulation predicts an RP-2 temperature rise in agreement with experiment, and a tube wall thermal state largely in agreement with experiment. The simulation results are used to identify regions of temperature, current flux density, and Joule heating concentration in the experimental apparatus. The predicted tube wall temperatures at each end of the heated portion of the tube are significantly less than the experimentally observed values. The predicted temperatures of the thermal chokes contacting the tube are considerably less than the experimentally observed values. The conclusion is drawn that an un-modeled thermal resistance or resistive heating source is present in the experiment.