Open fires: Experiments and theory

The open fire is used by millions of households around the world to perform a variety of tasks, the principal one being that of cooking in third world countries. Its virtues are simplicity of design and nearly zero cost. In this study we use it as a convenient tool for investigating certain general characteristics of woodburning stoves for cooking.The paper is in three parts. The first part delineates the influence of fuel, operating and design characteristics of open fires on the efficiency as determined by water boiling tests. The second part provides an insight into certain physical characteristics of wood-fires through instantaneous weight-loss measurements. In particular this part helps to explain the results of the first part. The final part provides anad hoc theoretical model which enables the calculation of radiant and convective heat transfer to a pan placed on an open fire. The theoretical calculations compare favourably with experimental results.