Modelling the thermal microenvironment of footwear subjected to forced ventilation.

In this paper, we develop a mathematical model of the thermal microenvironment in footwear that considers forced ventilation of the footwear cavity. The developed model was validated using a newly developed thermal foot-manikin system and the results show that the model effectively predicts the total dry thermal insulation of footwear under various dynamic conditions. The footwear cavity model is then integrated with a thermoregulation model, and the integrated model effectively predicts changes in foot skin temperature resulting from forced ventilation (0-90 L/min). At an air temperature of 26.4 °C and a foot thermal comfort temperature of 32.2 °C, the required minimum ventilation rate was found to be 5.4-24.6 L/min, which corresponds to a total static thermal insulation of footwear of 0.10-0.20 This indicates that ventilation can adequately control the thermal microenvironment of the footwear cavity, thereby maintaining foot thermal comfort. An adverse footwear thermal microenvironment results in foot thermal discomfort and foot hygiene problems. We hypothesise that forced ventilation may enable thermal control of footwear microenvironments. A mathematical model was developed which can determine the forced ventilation rate required in a given type of footwear to create foot thermal comfort.