تعيين خواص حرارتي - فيزيكي آب ليموترش

Determination of thereto-physical properties in lime juice is necessary for prediction, control, as well as control numerical modeling of processes, such as drying. These properties have been found to be affected by solid content as well as temperature. Therefore, properties including; thermal conductivity, density, specific heat and thermal diffusivity were determined at three levels of solid content, (12%, 19% and 25%), with temperatures from 35 to 78 °C. at eight levels. Thermal conductivity was measured by use of co-axial cylinder in the steady state condition, density by volumetric pycnometer, specific heat by differential scanning calorimeter in the transient state, and thermal diffusivity by employing the relationship among thermal conductivity, specific heat and density. Results indicated that both solid content and temperature greatly influence the properties. Density increased with increasing solid content or decreasing temperature while the other properties have been decreased with either increasing solid content or decrease in temperature. With multiple regression analysis, an empire model was proposed to predict thermo-physical properties of lime juice using operating variables. These models are linear with confidence factor (R2) for all of them being greater than 0.92.