Experimental measurement and finite element modeling of bioheat transfer with phase changes of molten metal in contact with porcine skin
Contact with molten metals can result in serious burn injuries. The bioheat transfer resulting from a 5 second exposure to 10 grams of molten copper brazing alloy with an initial temperature of 900°C is evaluated for four different conditions: uncovered skin, skin covered by cotton, skin covered by Nomex IIIA, and skin covered by a combination of cotton and Nomex IIIA. The transient temperatures are calculated via a finite element model, and experimental measurements are made using freshly excised porcine tissues instrumented with thermocouples in order to validate the finite element model. Additionally, the finite element model was analyzed for sensitivity to thermal conductivity, blood perfusion, char formation, and perspiration. The models predict that cotton is a better thermal insulator than Nomex IIIA. The model is found to be sensitive to char formation and perspiration, but less sensitive to thermal conductivity and blood perfusion. Additionally, a unique hydrophilic organic polymer is proposed as a substitute for dermal tissue in thermal injury studies in lieu of in vivo experimentation in animals and/or humans. The solid component of the polymer, a fine white powder known as TX-151, (Oil Center Research, Inc., Lafayette, Louisiana), is mixed with varying amounts of water and salt (NaCl) to form the sham material. Measured values for thermal conductivity, thermal diffusivity, and density fell within the ranges of values for like properties of human dermis reported elsewhere. Preparation and use of the sham material for application in experimental burn simulations is described.