A Model to Predict the Influence of Inconsistencies in Thermal Barrier Coating (TBC) Thicknesses in Pistons of IC Engines
subject: CFD Modeling; LHR engines; performance; Thermal Barrier Coatings (TBC); thickness deficiency
description: LHR (Low heat Rejection) engines comprise of components that are modified with ceramic Thermal Barrier Coatings (TBC) to derive improvements in performance, fuel efficiency, combustion characteristics and life. In addition to engine parameters, the ability of TBCs (250 - 300?m thick) to function favorably depends on materials technology related factors such as surface-connected porosity, coating surface roughness, uniformity and consistency in coating thickness [1]. Right since the nineties, emphasis has been placed on the complexity of piston contours from a coating processing standpoint because the piston bowl geometry although appears simple, is actually quite complex. Robotic plasma gun manipulation programs have been developed to obtain uniform coating properties and thicknesses which are highly classified information. Thicker coatings offer better thermal insulation characteristics but in thickness deficient regions, TBCs may be as thin as ?30 microns. Applied via the 'line of sight' process, in the Atmospheric Plasma Spray System the coating thickness does not get developed adequately if the components comprise of contours with shadow regions. Thus the coating quality of a LHR engine heavily depends upon the shape of the engine components. This affects the barrier effects offered by the TBC and is reflected via generation of unwanted thermal gradients in the combustion chamber and on the external piston walls that adversely influence the engine performance. Extensive diesel engine cycle simulation and finite-element analysis of the coatings have been conducted to understand their effects on (a) diesel engine performance and (b) stress state in the coating and underlying metal substructure. Research work presented here involves the need and developmental efforts made via Computational Fluid Dynamics (CFD) to generate a model via ANSYS - Fluent simulation software that predicts the temperature gradient across TBCs of various ceramics and coating thicknesses. Th…
creator: Ramaswamy P.; Shankar V.; Reghu V.R.; Mathew N.; Manoj Kumar S.
source: Materials Today: Proceedings, Vol-5, No. 5, pp. 12623-12631.
publisher: Elsevier Ltd
date: 2018-01-01
rights: Restricted Access
relation: ISSN: 22147853
format: Online
language: English
type: Conference paper
coverage: Ramaswamy P., Surface Engineering Laboratory, Department of Mechanical Engineering, Faculty of Engineering, Christ University, Bengaluru, 560 074, India; Shankar V., Surface Engineering Laboratory, Department of Mechanical Engineering, Faculty of Engineering, Christ University, Bengaluru, 560 074, India; Reghu V.R., Surface Engineering Laboratory, Department of Mechanical Engineering, Faculty of Engineering, Christ University, Bengaluru, 560 074, India; Mathew N., Mechwell Industries Limited, Bangalore, 560 074, India; Manoj Kumar S., Mechwell Industries Limited, Bangalore, 560 074, India