Numerical investigation of evaporation of a single ethanol/iso-octane droplet

Numerical study has been performed to analyse evaporation of a single droplet composed of a binary mixture of ethanol and iso-octane. The Navier–Stokes equations are solved in conjunction with VOF multiphase model to track the liquid/gas interface over time. Ethanol and iso-octane form a highly non-ideal mixture and therefore the UNIFAC group contribution method was used to determine the vapour–liquid equilibrium (VLE). Source terms due to interfacial mass transfer were implemented in the continuity, momentum, energy and species equations. Commercial computational fluid dynamics solver, Ansys Fluent 13.0 was used in this study. VLE, mixture transport properties and source terms due to interfacial mass transfer were implemented using user defined functions. Parametric study to analyse the effect of free stream temperature and composition, droplet temperature and composition was performed

Simulation of a gas blasted liquid sheet on GPU architecture

Atomization of liquid fuel from injector in gas turbine combustors is commonly achieved by means of coflowing gas stream. A study of the re presentative example of this scenario is presented in this paper. An in - house finite volume method based code is developed for this purpose. Volume of fluid (VOF) method is used for capturing the interface. Geometric multigrid method is employed for solvin g the pressure poisson equation and it is parallelized on Graphics processing unit ( GPU ) architecture to meet the computational demand required . The solver is validated for standard benchmark test cases. The solver is applied to study the effect of gas to liquid velocity ratio on primary atomization of liquid sheet

Numerical Investigation of In-Cylinder Fuel Atomization and Mixing For a GDI Engine

Gasoline Direct Injection (GDI) engines have been shown to have better fuel economy, transient response and cold-start hydrocarbon emissions. Additionally they have lower NOx emissions when operated under lean conditions. However, controlling charge stratification under various load conditions is a major challenge in GDI engines. In the present study a numerical simulations have been performed to understand factors affecting air/fuel mixture preparation under various engine operating conditions. Fuel spray atomization was studied using the two-way coupled Eulerian-Lagrangian approach. Momentum, energy and species equations were solved for the continuous gas phase. The droplet life history was tracked using the Lagrangian approach. Parameters like fuel injection time, fuel mass flow rate and engine speed was varied to determine their effect on air/fuel mixture preparation inside the cylinder. NOMENCLATURE A Area (m 2) B Spalding number Cd Coefficient of discharge Cp Constant pressure specific heat (kJ/kgK) do Injector inner diameter (m) Dp Droplet diameter (m) Fs Surface force (N) Fb Body force (N) g Acceleration due to gravity (m/s 2) he Heat transfer coefficient (WK/m

Numerical Analysis of Thermal Spray Coating Process

A numerical study of Thermal spraying process is required for optimizing performance and gun design for spraying various materials. Cold spray process is a new technique of thermal spray process which is used in industries and very limited data is available. This thesis presents an investigation on the powder stream characteristics in cold spray supersonic nozzles. This work describes a detailed study of the various parameters, namely applied gas pressure, gas temperature, size of particles, outlet gas velocity, dimensions of the nozzle on the outlet velocity of the particles. A model of a two-dimensional axisymmetric nozzle was used to generate the flow field of particles (copper or tin) with the help of a carrier gas (compressed) stream like nitrogen or helium flowing at supersonic speed. Particles are dragged by the carrier gas up to high velocity magnitudes, resulting in severe plastic deformation processes upon impact with a solid substrate positioned at the distance SoD (Standoff Distance). ANSY

Numerical Simulation of Hit Noise Generation Due to Sloshing Phenomenon in a Rectangular Tank Under Periodic Excitation

Sloshing in fuel tanks is one of the major sources of noise in hybrid and high-end vehicles. During sloshing, the fluid causes impacts on tank walls resulting in their vibration, which further leads to noise, referred to as “hit noise.” Therefore, hit noise generation is a multi-physics phenomenon involving fluid flow, structural response, and acoustic radiation. This paper presents a multi-physics approach to predict hit noise in a rectangular tank. The methodology involves the prediction of fluid loading on tank walls and their structural response using transient fluid and structural analyses which are weakly coupled. Radiated hit noise is predicted using acoustic finite element analysis. Longitudinal periodic excitation is applied to the fluid domain at different frequencies to simulate the sloshing regime which has dominant fluid–structure interactions. Parameters like tank wall pressures, the resulting dynamic acceleration, and radiated sound pressure levels are monitored and validated with the experimental results available in the literature

CFD Simulation of Actuated Micropump

Micropumps with various types of actuations have been using in microfluidic transport for liquid drug delivery. Due to the complexity of the flow field, particle transport through a valve less micropump might be challenging in comparison to a pressure-driven flow micropumps