Modelling and simulation of a temperature compensation device in a fuel control unit

A model is developed for the simulation of a temperature compensation device of a gas turbine engine main fuel control unit. For this purpose the appropriate conservation laws (mass, momentum and energy) are employed. Both the effects of temperature and pressure is taken into consideration for the calculation of the thermophysical properties of the working medium in order to accurately predict the thermal expansion and contraction of the actuating mechanism. The behaviour of the system (temperature, pressure and displacement) is described by a system of ordinary differential equations which is solved using a variable step Runge–Kutta algorithm of order 5(4). A parametric study is carried out comparing the system performance for various design variables such as the liquid mass, the heat transfer coefficient and two working mediums, ethanol and acetone.