Research Of Drying Process Of Longan And Thermodynamic Analysis Of Heat Pump Drying System

Drying technology has been widely used in industrial and agricultural production in all areas. Drying process is the production of energy in the course of a very large production processes, with the progress of science and technology, energy saving technology of this process is increasingly being recognized by society, the heat pump technology is an important way to them. Heat pump drying technology has the following advantages:high efficiency, wide range of temperature control can be used to achieve an oxygen-free inert medium drying, high degree of automation, environmental health and the drying time is short and so on. In this paper, GHRH-20 type high-temperature heat pump drying device, through a different approach, changing the heat pump drying temperature and wind speed and other factors affect the dried longan, dried longan heat pump technology launched a related study, longan and after drying drying curve analysis, texture analysis and sensory evaluation. The establishment of a mathematical model of heat pump drying longan, distribution and use of ANSYS software for the whole longan fruit drying temperature field was simulated, and the heat pump drying process was simple thermodynamic analysis and evaluation of heat pump dryers. Experimental results show:1. ANSYS Software Distribution whole fruit dried longan temperature field simulation, since the thickness of the outer husk longan is much smaller than the thickness of the stone and flesh, and the heat transfer characteristics of longan fruit shell is very good, therefore, study materials inside longan when the temperature field distribution approximate the skin and flesh of longan fruit shell stone layer as homogeneous material shall be suitably preheated before the whole fruit dried longan.2. Firstly, based on the GHRH-20 type high temperature heat pump dried longan drying apparatus to carry out the test, using a single factor analysis method, the heat pump drying longan drying process launched research. From different approaches (whole fruit peeled and pitted), drying temperature, wind speed longan drying rate, texture and sensory evaluation value factors affect drying. The results showed that:(1) handling and drying temperature has a significant influence on the drying time, drying wind speed had no significant effect on the drying time; (2) under the same kind of treatment, the drying temperature of the drying time, sensory evaluation has a significant influence, the drying time and the sensory evaluation were not affected by drying wind speed.3.Secondly, according to the single factor experiments, experiments to determine the influence of factors and factor levels, namely the drying rate, texture value, sensory evaluation value as a measure, test analysis using the overall balance method and analysis of variance to obtain the optimum parameters for the drying process:shelled whole fruit drying, drying temperature 60 ℃, drying wind speed 3 m/s.4. The last principle, to carry out analysis of the process of the heat pump drying, air drying medium cycle analysis to the first law of thermodynamics and the second law of thermodynamics, based on the principle of using exergy analysis of drying oven analyze energy uniform standards for providing a reasonable energy saving direction.