Bioheat Transfer
Mohammad Shams Kolahi; Ataollah Hashemi
Volume 5, Issue 1 , June 2011, , Pages 57-66
Abstract
Recent technological and industrial advances have increased the number of skin burns due to human body exposure to heat in a fire or hot and mechanized environment. In addition, hot environment can produce a strain on a human body leading to discomfort and heat stress and even death. In hot summer days, ...
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Recent technological and industrial advances have increased the number of skin burns due to human body exposure to heat in a fire or hot and mechanized environment. In addition, hot environment can produce a strain on a human body leading to discomfort and heat stress and even death. In hot summer days, many people suffer from heat stroke, dehydration and loss of body fluid. Therefore, the subject of studying thermal energy transport in living tissues is useful for assessing skin burns accurately, better understanding the thermoregulatory system of the body and for developing thermal protection standards. In a hot environment, the most important factor to control the body temperature is evaporation. Accordingly, this study solves one dimensional Pennes’ bio-heat equation by means of backward finite difference formulation. Physical and physiological factors taken into account are: sweat secretion, capillary blood circulation (perfusion), metabolic heat, heat and water exchange with the environment through convection and evaporation. Initially, the model is validated using the work of Zhao et al. Then, the evaporation term is added to the model to study the effect of ambient temperature variation on skin tissue temperature. The results show that thermal disease such as hyperthermia can be expected if uncovered skin is held for a specific time at hot environment. It is observed that increasing ambient temperature causes a shift in the location of the maximum temperature toward the surface of the skin, i.e., the maximum temperature occurs at the depth of about 9 and 7.6 mm of skin surface for ambient temperature of 50 and 60°C, respectively.
Fluid-Structure Interaction in Biological Media / FSI
Bahman Vahidi; Nasser Fatouraee
Volume 2, Issue 4 , June 2008, , Pages 285-296
Abstract
Arterial embolism is one of the major killers of the people who have heart diseases. In cerebral arteries, the danger of embolism is that the ruptured particles are carried into the brain, provoking neurological symptoms or a stroke. In this research, for the first time, we have presented a numerical ...
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Arterial embolism is one of the major killers of the people who have heart diseases. In cerebral arteries, the danger of embolism is that the ruptured particles are carried into the brain, provoking neurological symptoms or a stroke. In this research, for the first time, we have presented a numerical model to study the complete blockage of the human common carotid artery resulted from the physical motion of a blood clot bulk with spherical geometry in it. In the numerical model, a transient flow was assumed in an axisymmetric finite length tube. The incompressible Navier-Stokes equations were used as the governing equations for the fluid and a linear elastic model was utilized for the blood clot bulk. In order to model the contact conditions between the blood clot and arterial wall, an axisymmetric rigid contact model was used. The arbitrary Lagrangian-Eulerian formulation (ALE) was applied to analyze the solid large displacements inside fluid flow. The results indicated that during contact between stenosis and the clot, separation and reattachment regions were occurred on the stenosis extensively which are susceptible to thrombosis onset and growth. By abruption of the clot from the arterial wall during its passage through the stenosis, an extensive recirculation zone occurred downstream of the stenosis and beneath the moving clot bulk. Analysis of the clot motion and deformation have showed that when the clot passed the stenosis completely, the areas near the clot peak had a large tendency to expand which indicated the propensity of these areas to disperse.
