Study of the Effect of Heat Supply on the Hydrodynamics of the Flow and Heat Transfer in Capillary Elements of Mixing Heads Jet Thrusters

The article presents the results of experimental studies of hydrodynamics and those of loobman single-phase and two-phase flows in capillary nozzle elements propellant thrusters and the proposed method of their calculation. An experimental study was performed in capillaries with a sharp entrance edge of the internal diameter of 0.16 and 0.33 mm and a relative length 188 and 161, respectively, in pouring distilled water and acetone in the following range of parameters Reynolds number Re = (0,3 ... 10) · 10³, Prandtl number Pr = (2 ... 10), pressure p = (0,1 ... 0,3) MPa, the heat flux q = (0...2)×10⁶ W/m², the difference of temperature under-heating of liquid Δt_n = (5 ... 80)K. The dependences for calculation of single phase boundaries, the undeveloped and the developed surface of the bubble and film key singing of subcooled liquid. It is shown theoretically and experimentally confirmed the virtual absence of areas of undeveloped nucleate boiling in laminar flow. The dependence for calculation of hydraulic resistance and heat transfer in the investigated areas of current. It is shown that in the region of nucleate boiling surface in the flow in capillary tubes, influence of the formed vapor phase on the hydrodynamics and heat transfer substantially higher than in larger diameter pipes. (paper)