Multifidelity Simulation of a Dual Mode Scramjet Compression System using Coupled NPSS and FLUENT Codes

Abstract

A complete dual mode scramjet assembly code was built using Numerical Propulsion Simulation System and the performance of the engine was tested for an envelope of Mach number 3.5 to 6.0. Different numerical techniques were opted for varying the fidelity of the analysis with the highest fidelity consisting of 2D RANS CFD simulation. The interaction between the NPSS elements with the CFD solver was governed by the top level assembly solver of NPSS. The results of intercomponent interaction between the compression components with the rest of the engine after varying the fidelity of the numerical simulation according to the complexity of the situation are presented. The length of the shock train has been predicted using different methods. The transition Mach number where operation switches from ramjet to scramjet mode was also studied. The results stress the importance of accounting for intercomponent interactions during the design phase of the components.

Quasi-one-dimensional Scramjet Combustor Flow Solver Using the Numerical Propulsion System Simulation

“…Moreover, this equation doesn't take into account flow separation, which is an important behavior of the flow as the combustion process generates a high back pressure causing an adverse pressure gradient that separates the flow. Heiser and Pratt addressed this phenomenon by a constant impulse function method rather than incorporating it into the ODE [1,4]. Thus, the variation of the core flow area in the separation zone is unknown since no position variable is involved in the control volume analysis.…”

“…This ODE is the result of Shapiro's generalized one-dimensional flow analysis in which the three conservation equations, the equation of state, Mach number and the second law of thermodynamics are algebraically manipulated with an ideal gas assumption into a set of ODE's, each of which is the derivative of a flow property such as Mach number, pressure, temperature, etc. calculated in terms of changes in area, mass flow rate, total temperature and the effects of friction and body forces[4,11].…”

A Multifidelity Simulation Method for Internal and External Flow of a Hypersonic Airbreathing Propulsion System

“…Their results revealed complex flow physics in the integrated airframe propulsion system. Vijayakumar et al [18] implemented a quasi-one-dimensional combustor model in a numerical propulsion system simulation (NPSS) and simulated the flow field coupled with FLUENT code. In their work, a compression system a simulated with the FLUENT solver for off-design cases.…”

“…In their work, a compression system a simulated with the FLUENT solver for off-design cases. NPSS and FLUENT were combined in a process coupling method [18]. Complex flow physics were investigated in a dual-mode scramjet engine compression system operating in the range of Ma 3.5 to 6.0.…”

“…Their work demonstrates the importance of multifidelity and componentintegrated analysis. Owing to the lack of flame blowout prediction capabilities developed by Vijayakumar et al [18] and Vu and Wilson [6], Connolly et al [19] implemented a generalized DMSJ combustors model in NPSS that can identified four operation modes, including unstart, ramjet, scramjet and blowout of the combustor. Based on NPSS, they built a turbine-based combined cycle, which can operate from takeoff to above Mach 5, successfully simulating mode transition from turbomachinery to DMSJ operation.…”