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The work presented is a comparative analysis between Reynold’s Averaged Navier Stokes (RANS) and Large Eddy simulation (LES) description of turbulence to capture the in-cylinder flow structures. Simulations are performed using RNG k - € RANS model and LES one equation eddy viscosity model with Werner and Wengle wall model. ECFM combustion model has been used to achieve the desired rate of heat release when compared against the experiments. KH-RT spray model has been used to define the primary and secondary breakup of parcels. A Renault engine operating on Miller cycle has been chosen for this study. Consecutive perturbation method (CPM) available in Converge has been used to take the advantage of availability of higher number of cores to reduce the effective CPU time. Results of RANS simulation indicates that increase in valve overlap results in faster tumble decay compared to LES.

This state of art investigation report explains the limitations of Rosin-Rammler approach in comparison with breakup approach. The injection phenomenon of a commercial injector is simulated at various injection pressures, with Heptane (C7H16) in a spray bomb. It is observed that Breakup approach is better suitable in terms of correlation for spray modelling than the Rosin-Rammler approach when the injection pressures are 10 and 20 MPa, the SMD correlation shows also a good correlation at these pressures. At 4 MPa, correlation is a bit poorer, which is coherent as break-up models are best suited to high injection pressures configurations. Also, in each approach the primary dependent parameters are fine-tuned and their effects are discussed.

Automotive Diesel engines delivers more energy than gasoline because it burns the fuel more efficiently by compression process. Diesel engine piston plays an important role in delivering more power with the same volume of air-fuel mixture. To achieve this we need to have a better swirl (rotation of air inside the cylinder along the cylinder axis) to ignite the fuel by proper air-fuel ratio. In this project we target to improve the swirl motion for the proper mixing of fuel and air inside the combustion chamber by making tangential groves on the piston bowl. Different bowl designs are targeted to compare and analyse the effects of piston bowl by using CFD code (Commercial CFD code for engine specific).The intake port, combustion chamber roof, cylinder liner, piston bowl, intake valves and exhaust vales are considered for the 3D CFD modelling.

Electromagnetic brakes are found in a variety of applications. They offer tremendous advantages including: absence of fading, high braking torque and controllability. However they suffer from decreasing torque at low and high speeds. In this study, a novel concept of permanent magnet eddy-current brake is proposed that maintains a flat braking torque profile over a broad speed range. The principle is analytically investigated and numerically validated through finite element simulations using MAXWELL. It is demonstrated that a usably flat braking torque profile can be achieved by altering the path of eddy-currents by magnetic field orientation, thereby affecting the apparent rotor resistance.

This paper is focused on the experimental and numerical investigation of tumble motion on a single cylinder optical engine on three important parameters like engine load conditions, engine speed and level of tumble. Experiments are conducted in an optical engine and the velocity fields are measured with the aid of advanced particle image velocimetry (PIV) measurement technique. For simulation, multiple cases were considered to develop the numerical process for transient in-cylinder aerodynamics to capture the tumble motion and turbulence level in a Spark Ignited (SI) engine. The simulation results, velocity fields of each case were directly compared with the corresponding test results for different crank positions of the engine. On comparison, a good agreement between the measurement and the simulation is obtained for different configurations.

The main objective of this study is to determine the appropriate boundary conditions for the distribution of droplet sizes, speed of the fuel settling at the nozzle of the injector and droplet penetration by numerical simulation using STARCD for a 3-holes injector of ULC-GE. In this study, the Eulerian- Lagrangian approach has been used to model the multiphase domain. A new strategy has been adapted to model droplet initial conditions using the Rosin-Rammler distribution, which is determined by measurement of the Sauter Mean Diameter D₃₂ and the De Brouckere Mean Diameter D₄₃ by the MALVERN method. Further, these droplets undergo the phenomenon of atomization by secondary break-up method and evaporation in the Eulerian domain. The numerical model has been used to evaluate the effects of different initial condition of droplets by changing the discharge coefficient of the nozzle, and the initial droplet size distribution at the nozzle tip.

In this study, different designs of intake ports for two-stroke Ultra Low Cost Gasoline Direct Injection Engine (ULC-GE) has been analyzed to conclude on best design using steady state analysis in STAR-CD. The four types of intake ports design with two cylinders, each having fourteen ports, have been studied. The basic differences in designs are horizontal inlet entry (perpendicular to cylinder axis) and vertical inlet entry (in-line with cylinder axis) having rotation of flow clockwise and anticlockwise. Each type is further differentiated in eight cases with varying distances between axis of two-cylinder as 85mm, 88mm, 91 mm, 94 mm, 97 mm, 100 mm, 105 mm and 112 mm. These designs are analyzed for four different pressure drops as 10 mbar, 50 mbar, 100 mbar and 150 mbar.