ОБОСНОВАНИЕ АЭРОДИНАМИЧЕСКИХ ПАРАМЕТРОВ ЭЖЕКТОРА ТЕРМОВАКУУМНОГО ЭКСТРУДЕРА

Abstract

The article describes a new structural and technological scheme of a thermal vacuum extruder, where chambers for preliminary and final dehydration of the finished product interact with each other by means of an ejector. The steam pumped out of the final dehydration chamber by means of a vacuum pump moves to the high-pressure part of the ejector and is removed outside for regeneration of the thermal energy spent on machine technological process. Simultaneously, this air flow ensures the steam movement from preliminary dehydration chamber of the extruder to the low-pressure part of the ejector. In order to substantiate the aerodynamic parameters of the ejector by computer simulation methods, an ejector model of a thermal vacuum extruder was obtained on the basis of Solidworks Flow Simulation package, and its finite element analysis was also performed. The aerodynamic study of the ejector enabled to check the scheme operability and analyze the degree of steam removal from the chamber for preliminary dehydration of the extrudate. The air flow in the ejector was studied to obtain data on the required capacity (supply) of the vacuum pump and a map of distribution of air flows and pressures. Maps of pressure distribution inside the ejector and the pressure at the inlet to the low-pressure nozzle were obtained in the process of modeling the object of the research. We considered a model of an ejector with the initial volume parametres of the flow rate of 4 m3 / h and 8 m3 / h for the incoming high-pressure flow. The obtained results made it possible to substantiate the required flow rate of the vacuum pump and evaluate the degree of steam removal from the preliminary dehydration chamber. The ultimate goal of the data presented in the work is to increase energy efficiency of thermal vacuum treatment of plant raw materials and to simplify technological equipment adjustments for its implementation.