The medical herbs should be dried directly after harvesting, otherwise, insects and fungi spoilage them. Conventional drying methods such as open sun drying and conventional fuel dryers are not suitable, since they co...The medical herbs should be dried directly after harvesting, otherwise, insects and fungi spoilage them. Conventional drying methods such as open sun drying and conventional fuel dryers are not suitable, since they contaminate the herbs, decrease the drying efficiency and at the same time increase the drying cost. Therefore, the recent trend is toward the harnessing the renewable energy to dry the medical herbs. This paper presents a new controlled drying system, which uses a solar collector and an electric heater to heat the drying air, and a PV-WIND hybrid system to supply the required electric energy to the dryer electric load. This paper also presents the dynamic modeling, simulation, and control of the suggested thermal system (i.e., the solar thermal system and the electrical heater). Moreover, this paper, exhibits the different results of the thermal system, to check the effectiveness of this system that fulfills the requirements of the drying operation. The system results are found to satisfy the ultimate goals of the drying operation.展开更多
In recent years, the new type of tumble waste dryer has been promoted and developed. Heat generation through phase transition is an environmental, friendly and efficient heat transfer drying method. In order to know u...In recent years, the new type of tumble waste dryer has been promoted and developed. Heat generation through phase transition is an environmental, friendly and efficient heat transfer drying method. In order to know under what conditions the water vapor has higher heat transfer efficiency in the semi-circular cylinder and more sufficient liquid phase transition, and under what conditions the quantity of heat transferred can be exactly controlled, we carried out relevant work. Based on the analysis of two-phase heat transfer of rotating body, a three-dimension model of garbage dryer is established. Then, the commercial CFD software ANSYS Fluent is used to simulate the two-phase flow in the semi-circular cylinder, and the simulation calculation is carried out. Finally, the theoretical calculation results are verified by experiments. Calculated by the simulation results analysis: according to the industrial use of setting conditions, simulation calculation results can achieve convergence, namely water vapor through the pipe wall heat conduction. Finally condense into liquid water, and to ensure that the liquid cavity in the body has a higher volume fraction, water vapor phase change rate is of more than 90%, the Nusselt number of the heat transfer surface is 60 to 300.展开更多
文摘The medical herbs should be dried directly after harvesting, otherwise, insects and fungi spoilage them. Conventional drying methods such as open sun drying and conventional fuel dryers are not suitable, since they contaminate the herbs, decrease the drying efficiency and at the same time increase the drying cost. Therefore, the recent trend is toward the harnessing the renewable energy to dry the medical herbs. This paper presents a new controlled drying system, which uses a solar collector and an electric heater to heat the drying air, and a PV-WIND hybrid system to supply the required electric energy to the dryer electric load. This paper also presents the dynamic modeling, simulation, and control of the suggested thermal system (i.e., the solar thermal system and the electrical heater). Moreover, this paper, exhibits the different results of the thermal system, to check the effectiveness of this system that fulfills the requirements of the drying operation. The system results are found to satisfy the ultimate goals of the drying operation.
文摘In recent years, the new type of tumble waste dryer has been promoted and developed. Heat generation through phase transition is an environmental, friendly and efficient heat transfer drying method. In order to know under what conditions the water vapor has higher heat transfer efficiency in the semi-circular cylinder and more sufficient liquid phase transition, and under what conditions the quantity of heat transferred can be exactly controlled, we carried out relevant work. Based on the analysis of two-phase heat transfer of rotating body, a three-dimension model of garbage dryer is established. Then, the commercial CFD software ANSYS Fluent is used to simulate the two-phase flow in the semi-circular cylinder, and the simulation calculation is carried out. Finally, the theoretical calculation results are verified by experiments. Calculated by the simulation results analysis: according to the industrial use of setting conditions, simulation calculation results can achieve convergence, namely water vapor through the pipe wall heat conduction. Finally condense into liquid water, and to ensure that the liquid cavity in the body has a higher volume fraction, water vapor phase change rate is of more than 90%, the Nusselt number of the heat transfer surface is 60 to 300.
