A New Transient Bio-Heat Model of the Human Body

A new mathematical multi-segmented model based on an improved Stolwijk model is developed for predicting nude human thermal and regulatory responses within body segments and the environment. The passive model segments the body into the 15 cylindrical parts. Each body part is divided into four nodes of core, skin, artery blood, and vein blood. The body nodes interact with each other through convection, perfusion and conduction. In any body element, the blood exiting the arteries and flowing into the capillaries is divided into blood flowing in the core (exchanges heat by perfusion in the core) and blood flowing into the skin layer (exchanges heat by perfusion in the skin). The model calculates the blood circulation flow rates based on exact physiological data of Avolio [1], real dimensions, and anatomic positions of the arteries in the body. The circulatory system model takes into consideration the pulsatile blood flow in the macro arteries with its effect on the convective heat transport. The inclusion of calculated blood perfusion in both the tissue and the skin, based on the arterial system model and the heart rate is unique for the current model. The bio-heat human model is capable of predicting accurately nude human transient physiological responses such as the body’s skin, tympanic, and core temperatures, sweat rates, and the dry and latent heat losses from each body segment. The nude body model predictions are compared with published theoretical and experimental data at a variety of ambient conditions and activity. The current model agrees well with experimental data during transient hot exposures. The nude human model has an accuracy of less than 8% for the whole-body heat gains or losses and ±0.48°C for skin temperature values.