The Eulerian–Lagrangian Approach for the Numerical Investigation of an Acoustic Field Generated by a High-Speed Gas-Droplet Flow

Abstract

This paper presents the Eulerian–Lagrangian approach for numerical modeling of high-speed gas-droplet flows and aeroacoustics. The proposed hybrid approach is implemented using the OpenFOAM library and two different methods. The first method is based on a hybrid convective terms approximation method employing a Kurganov–Tadmor and PIMPLE scheme. The second method employs the regularized or quasi-gas dynamic equations. The Lagrangian part of the flow description uses the OpenFOAM cloud model. Within this model, the injected droplets are simulated as packages (parcels) of particles with constant mass and diameter within each parcel. According to this model, parcels moving in the gas flow could undergo deceleration, heating, evaporation, and breakup due to hydrodynamic instabilities. The far-field acoustic noise is predicted using Ffowcs Williams and Hawking’s analogy. The Lagrangian model is verified using the cases with droplet evaporation and motion. Numerical investigation of water microjet injection into the hot ideally expanded jet allowed studying acoustic properties and flow structures, which emerged due to the interaction of gas and liquid. Simulation results showed that water injection with a mass flow rate equal to 13% of the gas jet mass flow rate reduced the noise by approximately 2 dB. This result was in good coincidence with the experimental observations, where maximum noise reduction was about 1.6 dB.

Comparative Study of Droplet Diameter Distribution: Insights from Experimental Imaging and Computational Fluid Dynamics Simulations

“…Many existing studies in the field of CFD that focus on modeling droplet size and distribution primarily pertain to scenarios involving spray nozzles or jet flows. In these studies, the Volume of Fluid (VOF) CFD model has often been employed, despite its computational expense in comparison to the more efficient Eulerian model [27]. This method is not suitable for simulating a droplet absorber with multiple nozzles due to its high computational cost.…”

“…The measurement of droplet size and distribution using a high-speed camera and validation through CFD simulations are effective techniques for understanding and optimizing gas-liquid systems. In the present study, the assessment and characterization of water droplet size distribution utilized the less resource-intensive Eulerian-Lagrangian [27] approach. This method divides the gas-droplet flow into two distinct models: the continuous phase, described by the Eulerian model, and the discrete phase, represented by the Lagrangian model.…”

Multi-objective performance assessment of HVAC systems and physical barriers on COVID-19 infection transmission in a high-speed train

“…The Eulerian and the Lagrangian approaches are broadly two methodologies to simulate the dispersion of aerosols in CFD [ 13 , [20] , [21] , [22] ]. The researchers showed by comparing experimental data that both the Eulerian and Lagrangian approaches are suitable for modeling airborne particles [ 23 , 24 ].…”

An extension of the all-Mach number pressure-based solution framework for numerical modelling of two-phase flows with interface

“…For the single phase modelling including multicomponent gases, a pressure-based numerical tool employing the hybrid approximation of convective fluxes [9,10] was developed earlier. The solver has been validated against different physical conditions [11][12][13][14][15][16][17][18][19][20][21][22][23][24][25][26] and for the wide range of Mach numbers. The next step for the framework development was the adaptation for simulation of high-speed multicomponent real-gas flows [27,28] in context of consideration of the phase separation phenomenon.…”