A method for solving transient simulation models of thermal-fluid systems

Includes bibliographical references (page 45)This thesis presents the development and testing of a new dynamic simulation solution method for thermal-fluid system modelling. A digital programming procedure was written to increase the accuracy and efficiency of the current modelling method. A liquid rocket engine system model was used as a test case. The descriptive algebraic and ordinary differential equations were reduced to an algebraic set and solved simultaneously using the Newton-Raphson Iteration Method for non-linear equations. A matrix solution program was developed to solve the coefficient matrix by means of the Gauss-Jordan reduction scheme with pivot strategy incorporating added logic to eliminate all unnecessary calculations. The resulting program required 40% less computational time than the current program realizing a 10% reduction in computer costs. The transients predicted by this program correlate closer to test data than those transients predicted by the current program. This program demonstrated that for a large complex and iterative system, total program optimization is possible and that the same method can be applied to smaller system models