Numerical Benchmark for High-Reynolds-Number Supercritical Flows with Large Density Gradients

Abstract

International audienceBecause of the extreme complexity of physical phenomena at high pressure, only limited data are available for solver validation at device-relevant conditions such as liquid rocket engines, gas turbines, or diesel engines. In the present study, a two-dimensional direct numerical simulation is used to establish a benchmark for supercritical flow at a high Reynolds number and high-density ratio at conditions typically encountered in liquid rocket engines. Emphasis has been placed on maintaining the flow characteristics of actual systems with simple boundary conditions, grid spacing, and geometry. Results from two different state-of-the-art codes, with markedly different numerical formalisms, are compared using this benchmark. The strong similarity between the two numerical predictions lends confidence to the physical accuracy of the results. The established database can be used for solver benchmarking and model development at conditions relevant to many propulsion and power systems

Thermal Transport and Entropy Production Mechanisms in a Turbulent Round Jet at Supercritical Thermodynamic Conditions

“…Regarding numerical benchmarks for supercritical flows, Ruiz et al [24] performed a two-dimensional DNS to provide a validation test case for high Reynolds number supercritical flows with large density gradients in simple mixing layer configurations containing the essential features of real devices (geometry, thermodynamics and hydrodynamics). In the case of wall flows and heat transfer under trans-and supercritical conditions, Kawai [25] used a three-dimensional DNS to gain more insight into the turbulent boundary layer phenomena at supercritical pressure and the turbulent heat transfer characteristics.…”

Numerical analysis on mixing processes for transcritical real-fluid simulations

“…The configuration considered here is relevant for rocket engines, where a two-dimensional mixing layer of liquid oxygen (LOX) and gaseous hydrogen (GH2) is simulated. This case was proposed by Ruiz et al [32] as a benchmark case to test numerical solvers for high-Reynolds number turbulent flows with large density ratios. The LOX stream is injected at a temperature of 100 K, and GH2 is injected at a temperature of 150 K. The pressure is set to 10 MPa.…”

“…A sponge layer of length 5h at the end of the domain is included to absorb the acoustic waves. The computational mesh has 100 grid points across the injector lip, which is fine enough to give statistically converged solution [32].…”

“…The temperature field predicted by the double-flux model is significantly higher than that predicted by the FC scheme. [32] are also included for comparison, which was computed using the solvers AVBP and RAPTOR. AVBP uses a QC scheme for the simulation of transcritical flows, whereas RAPTOR is a FC solver with a dual time-stepping scheme.…”

“…The solver AVBP with a QC scheme and the FC solver RAPTOR were both used to simulate a benchmark test case of a LOX/GH2 mixing layer [32]. Despite similar behaviors of axial and transverse velocity profiles and species mass fractions, significant differences in both the mean and root-mean-square (rms) values of the temperature field were observed.…”