Experimental testing and geometric optimization of a domestic cooker burning 80%Natural-Gas+20%Hydrogen.

In urban pipelines, blending hydrogen into natural gas has been considered as an effective way of hydrogen usage to reduce carbon emission on household appliances. However, few studies, especially experimental ones are dedicated to address the characteristics of a typical domestic cooker due to the transition from natural gas to 20%hydrogen-enriched natural gas. This study experimentally investigated the changes in terms of the gas flow rate, flame temperature, heat transfer and emission characteristics of a domestic cooker as a result of such transition. Using a self-developed gas blending system, the flow rates of the both the mixed fuel and its components are obtained. The data shows that after blending hydrogen, the mixed gas flow rate becomes higher. Compared to the original cooker burning natural gas, hydrogen blending results in a decreased natural gas flow rate, leading to lower carbon emission. In addition, the thermal input to the cooker is lowered and hydrogen blending leads both the inner and outer combustion zones of the flame to shorten while the flame temperature to increase. As an attempt to optimize the performance of the cooker, the effects of wok stand height on heat transfer efficiency and NO/NO x /CO emissions are examined. It is found that the cooker fueled by 20%hydrogen-enriched natural gas exhibits lower heat transfer efficiency, higher NO/NO x emissions and lower CO emission. According to the fact that the heat transfer efficiency increases at lower wok stand height, the wok stand height is lowered from its original 7 cm–6 cm and 5 cm. The finding indicates that when the wok stand height is moderately decreased to 6 cm, NO/NO x emissions decrease and CO emission is only marginally increased. This study proposes that when natural gas is replaced by 20%hydrogen-enriched natural gas on a swirl flame cooker, the wok stand height can be slightly lowered to exploit the advantages of blended hydrogen combustion. • A systematic experimental study of the flow/temperature/emission/heat transfer of a cooker. • The changed flow rates are measured by using a self-developed device. • The height of the swirling flame shortens after blending hydrogen to natural gas. • The flame temperature/NOx emission increase while CO emission decrease. • Lowering the wok leads to higher heat transfer efficiency, lower NO x while only marginally higher CO. [ABSTRACT FROM AUTHOR]