Estimation of the Wetting Efficiency of an Evaporator by a Dual Extended Kalman Filter

Abstract

This work presents the development of a Dual Extended Kalman Filter (DEKF) used to calculate the parameter known as wetting efficiency of a falling film evaporator. The wetting efficiency refers to the part of the tube that is in contact with the falling film. This parameter depends on different factors as the type of surface, physical properties of the fluid, and mainly the mass flow rate. The knowledge of the value of this parameter gives information about the lack or the abundance of the mass flow rate of the falling film. The evaporator consists of 13 tubes, in which the wetting efficiency of the first tube is estimated using the experimental outlet temperature of the fluid flowing inside the tubes. The results show that the predicted temperature for the first tube matches adequately the measured temperature. Alternatively, the wetting efficiency and the overall heat transfer coefficient were estimated together as a single parameter. The results show that both approaches can be used to estimate the unknown evaporator parameters, however, estimating the wetting efficiency gives more system information because it determines the lack of fluid on the tubes.