Soft Sensor Modeling for the Vacuum Characteristics of a Direct Air-Cooled Turbine Unit by Using Mechanism Analysis

To establish soft sensor model for the vacuum characteristics of a direct air-cooled turbine unit (DATU), the heat-transfer-unit method was applied on the based of the heat transfer mechanism model in this study. The proposed soft sensor model consists of a three-step strategy as follows. Firstly, the rule of fouling resistance (FR) outside tube was studied, and a new algorithm was presented by using the correction coefficient of FR outside tube to the linear correction of heat transfer coefficient. Secondly, the parallel operation characteristics of air-cooled fans were analyzed. Finally, the established soft sensor model was validated with the test data. In addition, the vacuum characteristics of the DATU were analyzed. These realize the predictive analysis of the vacuum characteristics of the DATU and lay a good foundation for the further study on the optimization of fans in the vacuum system.