A novel simulation theory and model system for multi-field coupling pipe-flow system

Dynamic Modeling and Full-Process Simulation of the Core Engine Test Rig Main Test System

“…Table 1 shows the module information of seven typical components generated by modularization disassembly of the main test system, of which the fluid source, gas pipe, gas volume, gas mixing apparatus, gas valve are five basic modules, based on which gas steady apparatus is obtained by combination development; the heater exchange cold gas (also can be called heater) has an heat-transfer increasing-temperature effect only in the high-temperature operating condition and is equivalent to the gas pipe module component under the normaland low-temperature operating conditions. The derivation source of modularization models of all these typical components is a flow/heat transfer two-field coupling subsystem derived from a multi-field coupling pipe-flow system simulation theory and model system [16], including the finite volume model of quasi-one-dimensional compressible variable-section pipe flow transient flow field and the finite volume model of pipe-wall transient heat transfer. Below gives the model derivation method for three modules, GV, GSA, and GMA.…”

“…For the wall of the gas valve inlet channel (inlet chamber) and outlet channel (outlet chamber), one of the radial one-dimensional heat transfer model, the zero-dimensional heat transfer model, and the adiabatic model [15,16] can be selected based on the actual condition of the temperature field.…”

“…However, since their components models come from different fields, the biggest problem in the basic simulation theory of the system-level model systems represented by these software is the absence of a system-level unified and comprehensive set of basic equations in integral or differential form, and the absence of a derivation process of component model from such an equation set in combination with the structure of typical component. To solve this problem, [16] proposes a simulation theory and model system for a flow, heat transfer, and combustion multi-field coupling pipe flow system. Its flow-field model can consider many factors, such as multispecies chemical reaction, species diffusion, variable volume, variable properties, fluid axial heat conduction, pipe-wall heat transfer, gravity field, and friction effects.…”

“…in the pipeline system need to be derived from the three systems, various reaction mechanisms need to be introduced into the components which consider the chemical kinetic effect, and suitable valve-spool/orifice throttling models need to be used for the components with throttling effect. The previous researches [15,16] commonly provide clear modeling solutions for the throttling problem of the valves with known information (i.e., structure and throttling characteristics) but seldom mentions the throttling modeling method for those valves without such information. This paper takes the modeling of a core engine test rig system with both known and unknown information valves as an opportunity to give a comprehensive solution to the key issue of the system-level spool/orifice throttling modeling.…”

“…The model of gas mixing apparatus is often studied on component level and uses Fick's law, and it generally does not consider wall heat transfer in the process of gas mixing [45,46]. The modularization simulation models are derived from the flow/heat transfer two-field coupling pipe-flow model subsystem [16,24] in combination with the typical component structure. The effectiveness of the model system is verified by comparing the simulation results of the whole process of the system in two operating conditions with the test results, so it can be used as a building block for a so-called digital twin.…”