investigation of specific heat and thermal conductivity of rasa grape (vitis vinifera l.) as a function of moisture content

kurdistan rasa grape is one of the delicious and sweet fruits with black color. it contains vitamins e, c and some protectors such as antioxidants. in order to design equipments and facilities for drying, preservation and processing of rasa grape, it is necessary and important to know about its specific heat and thermal conductivity. in this paper the specific heat and thermal conductivity of rasa grape were studied. the method of mixtures and hot wire as a heating source was used for measuring the specific heat and thermal conductivity, respectively. the experimental variables were temperature at four levels of 40, 50, 60 and 70 °c and moisture content at four levels of 22.36, 37.56, 52.13 and 71.53%. the results showed that the specific heat and thermal conductivity of rasa grape increased linearly from 1.6523 kj kg-1°c-1 to 3.3253 kj kg-1°c-1 and 0.1252 w m-1°c-1 to 0.4202 w m-1°c-1 respectively, with increasing moisture content and temperature. the results also showed that the effect of moisture content on increasing the specific heat and thermal conductivity was more significant than that from temperature rise.