Search Results

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.

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.