Experimental investigation of blended H2/CH4 combustion in combustors with block for micro-thermophotovoltaic

Abstract

To extend the operation conditions and improve the working performance of micro-thermophotovoltaic system, the combustor with varied block setting and length is proposed, where blended CH4/H2 is employed. Effects of CH4 addition, burner dimensions and parameters on combustion characteristics, energy conversion and multi-factors on working performance are investigated under various flow rates. Results demonstrate that the consumption and production of OH and H radicals are strongly impacted by the CH4 blending ratio, affecting the flame regime, burning heat release and heat transfer in the combustion chamber. And 5–15 % CH4 addition is beneficial to the improvement of burner thermal performance, where the highest radiation temperature is achieved at mCH4 = 15 % in combustor C24-0.4 under lower fuel flow rate, while it is also affected by the burner setting. A higher CH4 mixing ratio contributes to the combustor with thin block and the thicker block with lower CH4 addition can both contribute to achieve a better working performance. Besides, the augment of burner length extends the operating conditions and the radiant area, while it reduces Tw, and combustor C29-0.6 obtains the highest radiation power of 48.1 W and electrical power output of 2.9 W with a system efficiency 2.2 % at mCH4 = 10 %, Vf = 635 mL/min and Φ = 1.0. So, the appropriate CH4 addition, block setting and burner size can yield enhanced system performance.