Population balance modeling in Simulink: PCSS

In this work we develop, demonstrate, and distribute the code for a new Simulink block that models the dynamic evolution of the population density function for a physical system which can be modeled by a population balance equation. The name of the block is PCSS, for population balance modeling using the conservation element/solution element method in Simulink. The block interfaces with an auxiliary user-defined function that allows the user to specify arbitrary expressions for growth and generation/loss terms, as well as an arbitrary number of inputs, outputs and auxiliary states for the block. The versatility of the block allows a wide variety of physical systems to be modeled, and the implementation in Simulink facilitates rapid model development and permits the use of pre-existing MATLAB/Simulink packages for system identification and control.