Characterization of Hollow Cone Gas Jets in the Context of Direct Gas Injection in Internal Combustion Engines

Deshmukh, Abhishek Y.; Vishwanathan, Giridar; Bode, Mathis; Pitsch, Heinz; Khosravi, Maziar; Bebber, David van

doi:10.4271/2018-01-0296

Cited by 21 publications

(13 citation statements)

References 33 publications

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“…Due to higher than critical pressure ratios and varying cross sections, the flow within the nozzle reaches supersonic velocities. Previous simulations in Deshmukh et al 30 showed that the boundary layer is very thin in the nozzle and has a minor impact on the flow except at the exit, where flow separation occurs. Therefore, the viscous effects are neglected, and the Euler equations are considered for modeling the nozzle gap.…”

Section: Model Developmentmentioning

confidence: 98%

“…A state-of-the-art compressible solver CHRIS (Compressible High-speed Reactive Solver) developed by Cascade Technologies Inc. is used for high-fidelity LES. 33 For details on the numerical schemes and setup information, the reader is referred to Deshmukh et al 30 The flow variables from the quasi-1-D model are compared with the flow variables on the centerline of the nozzle gap from the 3-D LES data. This comparison is valid because the wall boundary layer in 3-D LES is found to be thin due to the high-speed flow through the nozzle resulting in almost top-hat profiles.…”

Section: Model Developmentmentioning

confidence: 99%

“…This comparison is valid because the wall boundary layer in 3-D LES is found to be thin due to the high-speed flow through the nozzle resulting in almost top-hat profiles. 30 The comparison is made for different nozzle pressure ratios (NPRs) ranging from 3.5 to 15 with helium and methane as working fluids.…”

Section: Model Developmentmentioning

confidence: 99%

“…For validation of the DCS model, two previously published cases are chosen. The first case is a temporal evolution of a gas jet in quiescent air 30 and the second case is a cold flow simulation of full engine cycle with injection. 24…”

Section: Validation: Dcs Modelmentioning

confidence: 99%

“…In this work, the injector model is developed and validated against LES of nozzle flow for different pressure ratios. The temporal evolution of the hollow-cone gas jet into ambient air with fixed and moving injector needle in the model is evaluated against Schlieren experiments and three-dimensional (3-D) simulations reported in Deshmukh et al 30 The model is then applied to a full cycle engine simulation and compared with PIV measurements and simulations with the MBC approach previously published in Deshmukh et al 24…”

Section: Introductionmentioning

confidence: 99%

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A quasi-one-dimensional model for an outwardly opening poppet-type direct gas injector for internal combustion engines

Deshmukh

Giefer

Goeb

et al. 2019

International Journal of Engine Research

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Direct injection of compressed natural gas in internal combustion engines is a promising technology to achieve high indicated thermal efficiency and, at the same time, reduce harmful exhaust gas emissions using relatively low-cost fuel. However, the design and analysis of direct injection–compressed natural gas systems are challenging due to small injector geometries and high-speed gas flows including shocks and discontinuities. The injector design typically involves either a multi-hole configuration with inwardly opening needle or an outwardly opening poppet-type valve with small geometries, which make accessing the near-nozzle-flow field difficult in experiments. Therefore, predictive simulations can be helpful in the design and development processes. Simulations of the gas injection process are, however, computationally very expensive, as gas passages of the order of micrometers combined with a high Mach number compressible gas flow result in very small simulation time steps of the order of nanoseconds, increasing the overall computational wall time. With substantial differences between in-nozzle and in-cylinder length and velocity scales, simultaneous simulation of both regions becomes computationally expensive. Therefore, in this work, a quasi-one-dimensional nozzle-flow model for an outwardly opening poppet-type injector is developed. The model is validated by comparison with high-fidelity large-eddy simulation results for different nozzle pressure ratios. The quasi-one-dimensional nozzle-flow model is dynamically coupled to a three-dimensional flow solver through source terms in the governing equations, named as dynamically coupled source model. The dynamically coupled source model is then applied to a temporal gas jet evolution case and a cold flow engine case. The results show that the dynamically coupled source model can reasonably predict the gas jet behavior in both cases. All simulations using the new model led to reductions of computational wall time by a factor of 5 or higher.

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Section: Model Developmentmentioning

confidence: 98%

Section: Model Developmentmentioning

confidence: 99%

Section: Model Developmentmentioning

confidence: 99%

Section: Validation: Dcs Modelmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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