Numerical study on flow condensation in subcooled oxygen bend pipes of liquid rocket.

This paper presents a numerical study on the flow condensation of gas oxygen in subcooled liquid oxygen within a liquid rocket pump cryogenic pipeline. A CFD model is established and flow field details such as phase distribution and flow condensation length are obtained. Experimental validation of numerical model is performed with R123, and the calculated void fraction and condensation length show good agreement with those of experimental data. Numerical results indicate that gas oxygen forms a continuous annular gas film and the temperature drops appreciably in the vertical section. Rapid condensation of oxygen occurs in the bend section and the following horizontal section. The condensation length of gas oxygen varies with the inlet gas to liquid ratio, subcooling and inlet velocity of liquid oxygen. The critical values of the gas/liquid ratio, liquid subcooling and inlet velocity for complete condensation in the given bend pipe is obtained.