Numerical and experimental study on the performance of a hybrid draft biomass cookstove

Over 2 billion people worldwide rely on biomass for cooking and primarily use traditional cookstoves, causing 4 million casualties annually due to indoor air pollution. This can be minimised by improving the design and combustion characteristics of the stoves. The present study is an attempt to achieve these improvements by investigating numerically (3D) and experimentally the thermal and emission performance of a newly developed hybrid draft biomass cookstove (HDBC). The influence of secondary air mass flow rate on stove performance is analysed. A homogeneous combustion is modelled to evaluate thermal performance, and soot formation is studied using three soot models: one-step, two-step, and mass-brook. The numerical results are validated against Water Boiling Test (WBT) data. The HDBC achieved Tier 3 level in efficiency and Tier 4 level in CO and PM2.5 emission performance, both experimentally and numerically, thus outperforming standard natural draft stoves. The numerical results exhibited fair agreement with the experimental data, with an average deviation of 6%, 9%, and 26% for efficiency, CO, and PM2.5 emissions, respectively, compared to the experimental results. The soot generation predicted by a one-step soot model gives better results over the other two models and is in good agreement with the experimental results.