The first part of the three parts that this work is divided into describes the simulation of a two-spool, two-stream turbofan engine modeled independently using Modelica (Dymola), MATLAB/Simulink and the Numerical Propulsion System Simulation (NPSS). The model contains steady-state performance maps for all of the components and has control volumes where continuity and energy balances are maintained. Rotor dynamics and duct momentum dynamics are also included. Steady state design and off-design points as well as transients can be simulated. The results of the simulation using the three modern tools are compared with the published results obtained using DIGTEM (Digital Computer Program for Generating Dynamic Turbofan Engine Models) and the pros and cons of each modern program are examined.
The second part describes the experimental results obtained by measuring pressure losses across gate, butterfly and ball valves subjected to compressible flow. Experimental data has been collected for all possible combinations of gate, butterfly and ball valves with nominal diameters of 0.5", 0.75", 1", and 1.25" and various valve flow areas, i.e. fully open, three quarter open, half open, and quarter open. The results have been compared to a similar study conducted using a ball valve with a nominal diameter of 1.5".
The third and final part uses the results of the above two parts and describes the development and simulation of a natural gas transmission model. A gas turbine engine drives a compressor that is used to pump natural gas through a pipeline. Upstream of the compressor is a throttling valve used to control the mass flow rate. Downstream, the Weymouth equation is used to model the volumetric flow rate and pressure losses in the pipeline.