AUTHOR=Yuchao Gao , Wei Chu , Yuan Xie , Chuanjin Jiang , Boqi Xu , Lingyu Su , Yiheng Tong 

TITLE=Investigations on Spray Characteristics and Self-Pulsation of a Gas-Centered Shear Coaxial Injector

JOURNAL=Frontiers in Energy Research

VOLUME=10

YEAR=2022

URL=https://www.frontiersin.org/journals/energy-research/articles/10.3389/fenrg.2022.887368

DOI=10.3389/fenrg.2022.887368

ISSN=2296-598X

ABSTRACT=<p>The spray characteristics of a gas-centered shear coaxial injector under different conditions and recess ratios (RR) were studied through experiments and numerical simulations. The numerical study was carried out based on the coupled level set and volume-of-fluid (CLSVOF) method and the adaptive mesh refinement (AMR) method. The results indicated that without recess, the spray angle first stayed almost constant and then dropped linearly with an increase in the gas mass flow rate <inline-formula id="inf1"><mml:math id="m1" xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mrow><mml:mrow><mml:mo>(</mml:mo><mml:mrow><mml:msub><mml:mrow><mml:mover accent="true"><mml:mi>m</mml:mi><mml:mo>˙</mml:mo></mml:mover></mml:mrow><mml:mi>g</mml:mi></mml:msub></mml:mrow><mml:mo>)</mml:mo></mml:mrow></mml:mrow></mml:math></inline-formula> when holding the liquid mass flow rate <inline-formula id="inf2"><mml:math id="m2" xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mrow><mml:mrow><mml:mo>(</mml:mo><mml:mrow><mml:msub><mml:mrow><mml:mover accent="true"><mml:mi>m</mml:mi><mml:mo>˙</mml:mo></mml:mover></mml:mrow><mml:mi>l</mml:mi></mml:msub></mml:mrow><mml:mo>)</mml:mo></mml:mrow></mml:mrow></mml:math></inline-formula> constant. In contrast, with recess, the spray angle was found to increase with <inline-formula id="inf3"><mml:math id="m3" xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mrow><mml:msub><mml:mrow><mml:mover accent="true"><mml:mi>m</mml:mi><mml:mo>˙</mml:mo></mml:mover></mml:mrow><mml:mi>g</mml:mi></mml:msub></mml:mrow></mml:math></inline-formula>, which could be attributed to the secondary expansion of the central gas flow. Under specific conditions, self-pulsation occurred and was accompanied by a loud scream. The frequency of the self-pulsation increased with both <inline-formula id="inf4"><mml:math id="m4" xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mrow><mml:msub><mml:mrow><mml:mover accent="true"><mml:mi>m</mml:mi><mml:mo>˙</mml:mo></mml:mover></mml:mrow><mml:mi>g</mml:mi></mml:msub></mml:mrow></mml:math></inline-formula> and <inline-formula id="inf5"><mml:math id="m5" xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mrow><mml:msub><mml:mrow><mml:mover accent="true"><mml:mi>m</mml:mi><mml:mo>˙</mml:mo></mml:mover></mml:mrow><mml:mi>l</mml:mi></mml:msub></mml:mrow></mml:math></inline-formula>. Moreover, the self-pulsation frequency decreased with RR. Meanwhile, the mechanism of self-pulsation was initially explored through numerical simulation. It was concluded that self-pulsation was caused by the surface tension and the pressure difference between the inside and outside of the liquid sheet, together with the central airflow impact extrusion.</p>