The main objective of our project is to form a low-order set of equations that can be used to estimate the properties of the flow through a turbofan bypass duct, based upon the existence of a heat exchanger in the flow. The main independent variable is the porosity of the heat exchanger, which is simply represented as the ratio of the open area of the face to the total area of face. These equations will be formed using theoretical calculation, ANSYS Fluent simulations, and physical test rig experimentation. These three studies will be compared and contrasted in order to create reliable equations.