Experimental and theoretical study of combustion efficiency of hydrogen‐oxygen mixture at pressure of 0.25 to 6.0 MPa

Summary The paper presents the new results of experimental and theoretical studies of combustion processes in hydrogen‐oxygen mixtures. Considered the impact of pressure in the combustion chamber on the efficiency of hydrogen fuel combustion. Experimental research results showed that the hydrogen content on the exit from the first and second sections of the experimental combustion chamber was 5.674% mass and 0.719% mass, respectively, at the pressure of 1.0 MPa. The proposed pressure range extension is based on computational experiments relating mathematical modeling of the processes occurring in the experimental setup, in particular, for the pressure in the combustion chamber and flame tube ranging from 0.25 to 6.0 MPa. The obtained results were verified. The accuracy in estimating the temperature of combustion products found due to the computational and physical experiments is in the range of 98.89%‐102.37% at the outlet of the first section, and is in the range of 97.38%‐97.86% at the outlet of the second section. Meanwhile, the accuracy in estimating the hydrogen underburning is in the range of 100.37%‐101.53% at the outlet of the first section, and is in the range of 98.81%‐99.05% at the outlet from the second section. Computational experiments show that an increase in the combustion products pressure leads to an increase in the combustion products temperature at the exit from the first section was within 1264°C‐1713°C range, and on the exit from the second section was within 937°C‐1386°C. It is shown that the recombination rate achieved in the experimental setup and computational experiments was 10.718 to 10.814 kg/(kg·s) at the pressure from 0.25 to 6.0 MPa. In this case, the minimum time necessary to complete recombination of combustion products was 0.5478 to 0.55 s under given conditions of external cooling. The pressure range in the combustion chamber does not significantly affect the mass fraction unreacted hydrogen. Experimental study of hydrogen‐oxygen combustion. Computational experiment based on computational fluid dynamics. Evaluation of pressure effects on the efficiency of hydrogen fuel combustion. Objectives of recombination rate of combustion products.