Mechanical Engineering for Society and Industry

Uniform heat distribution is essential for staged drying of coconut-shell briquettes because temperature overshoot can induce thermal shock and reduce product quality. This study evaluated the thermal performance of an industrial biomass-fired briquette oven using transient computational fluid dynamics (CFD). The oven was equipped with a 20 kW burner that supplied 500 °C gas to a stainless-steel straight-tube heat exchanger and a ceiling-mounted blower that delivered 3 m³/s downward airflow. A transient three-dimensional CFD model incorporating incompressible ideal-gas flow, the SST turbulence model, P1 radiation, and conjugate heat transfer was used to compare wall-mounted and floor-mounted heat-exchanger configurations. The wall-mounted configuration generated stronger forced-convection recirculation and more uniform heating, with a mean temperature of 81.95 °C, ΔT of 10.57 °C, and a coefficient of variation of 3.75%. The floor-mounted configuration achieved a higher heating capacity, with a mean temperature of 108.14 °C and stored thermal energy of 3.02 MJ, but it showed poorer uniformity, with ΔT of 32.23 °C and a coefficient of variation of 8.79%. Heating efficiency increased from 32.5% for the wall-mounted case to 43.1% for the floor-mounted case. The results reveal a clear trade-off between temperature uniformity and heating capacity and provide a comparative numerical basis for evaluating heat-exchanger placement under the investigated operating conditions.