Assessment of the risk of poisoning by combustion products from domestic gas-fired appliance using CFD modeling

Abstract

Gas-fired appliances, including water heaters, are widely used in households and may have a significant impact on their gas atmosphere, i.e. reduction of oxygen concentration and appearance of toxic oxides (especially CO). Therefore, the paper deals with the assessment of the risks of poisoning by combustion products from a gas appliance using CFD modeling. A three-dimensional numerical CFD (Computational Fluid Dynamics) model of a real apartment was developed, in which the gas-fired instantaneous water heater with a standard power of 20 kW works in the bathroom. The model enabled the performance of transient simulation calculations for various air inflows (ventilation) to the abovementioned apartment (30 - 120 m3/h) as well as for various concentrations of carbon monoxide in combustion gases (0.1 - 1%). It was assumed that combustion gases inflow entirely into the room for 10 minutes. Based on the calculations performed, it was shown that the main threat occurs in the room where gas-fired water heater is located, i.e. in the bathroom. Moreover, changes in concentration of carbon monoxide and oxygen over time, and depending on the room height, were analysed. In addition, an analysis of the impact of combustion gases inflow on the temperature in the bathroom and the whole apartment was made.