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Prediction of cell characteristics and its thermal behavior is critical to design and optimize thermal management system for electric vehicle battery pack. In the present paper experimental and numerical study is carried out to characterize the thermal behavior of electrochemical cell under constant discharge rate. 3D numerical model is developed for 18650 lithium-ion cylindrical cell. Average temperature of single cell and cell pack is estimated for a constant discharge rate. Air and naphthenic oil at 298K is considered as working fluid. The result shows a significant reduction in battery module cell average temperature of 6.6 ℃ for 1C discharge and 9.8 ℃ for 2C discharge using oil as compared to air. Present numerical results are validated with experimental study for a single cell and 3 × 3 battery module under natural convection and are found to be in good agreement.

A phenomenological model for diesel and natural gas dual-fuel combustion for low diesel percentage has been successfully developed. The spray was divided into multiple zones to account for concentration and temperature gradients and stratified entrainment of charge into the spray. Similarly, the premixed “air + NG” burnt gases as combustion progresses were divided into multizones and, hence, could predict the temperature gradients. The combustion model has been validated on available experimental data published in literature. A full-cycle simulation was attempted to evaluate the overall performance of a dual-fuel engine in terms of indicated power at different parametric conditions. The model predictions were compared with experimental pressure time histories and observed to be closely matching.

Interest in operational cost reduction is driving engine manufacturers to consider low-cost fuel substitution in heavy-duty diesel engines. These dual-fuel (DF) engines could be operated either in diesel-only mode or operated with premixed natural gas (NG) ignited by a pilot flame of compression-ignited direct-injected diesel fuel. Under certain conditions, dual-fuel operation can result in increased cycle-to-cycle variability (CCV) during combustion. CFD can greatly help in understanding and identifying critical parameters influencing CCV. Innovative modelling techniques and large computing resources are needed to investigate the factors affecting CCV in dual-fuel engines. This paper discusses the use of the High Performance Computing resource Titan, at Oak Ridge National Laboratory, to investigate CCV of a dual-fuel engine.

Phenomenological flame propagation model is critical for predicting performance and emissions of spark ignition (SI) engines. A multi-zone phenomenological model offers better accuracy in predicting the emission trends. Hence, in the present work, a multi-zone phenomenological SI flame combustion model is formulated and validated with engine data from published literature. The formulation includes turbulence, combustion, flame propagation, flame geometry interaction with solid walls, gas-to-wall heat transfer, CO and NO emissions from burnt zones and HC emission from quench layer. A knock model has also been implemented. The key contributions are implementation of k-epsilon turbulence model which takes care of contribution from squish/swirl/combustion, predictive multi-zone flame propagation model and a decisive zoning scheme based on percentage of fuel burnt.

Fuel-air mixing during the early period has a significant influence on the combustion and emission processes of small diesel engines where combustion duration is short. The mixture heterogeneity during the premixed phase influences the premixed burnt fraction and the peak rate of energy release. The premixed burnt fraction is affected by engine speed, air swirl and fuel injection. In diesel engines, injection parameters, piston configuration and induction swirl interact with each other and have an optimum condition for a better performance. The present paper is an attempt to investigate these effects using an improved existing analytical model. The results concerning the effects of swirl and injection conditions on fuel-air mixing pattern, the premixed mass fraction and the rate of energy release at the instant of ignition, and duration of combustion on engine combustion and emission characteristics are presented.