Abstract In this paper, we analyze the impact of in-service deterioration on overall thermal performance (metal effectiveness) heavily cooled high-pressure nozzle guide vanes a design typical large civil jet engines. We study 15 deteriorated parts (increased surface roughness, barrier coating spallation and sintering, damaged film cooling holes, trailing edge burn-back) from operational engines...

In this paper, the effect of the Intake Valve Deactivation (IVDA) on engine performance is investigated in detail. Based on an optimization platform with Genetic Algorithm (GA) and engine thermodynamic model, the characteristics of the engine volumetric efficiency and pumping loss were studied under the cam-drive, Single Intake Valve (SIV) and Dual Intake Valves (DIV) operating modes, and the e...

Aircraft engines constitute a comp‌lex system, requiring adequate mon-itoring to ensure flight safety and timely maintenance. The best way to achieve this, is modeling the engine. Therefore, in this paper, a suitable mathematical model from engine controller design point of view, for a specific aero turbine engine is proposed by the aid of MATLAB/Simulink software. The model is capable of reduc...

This paper presents an advance in monitoring and process control of surface roughness in CNC machine for the turning and milling processes. An integration of the in-process monitoring and process control of the surface roughness is proposed and developed during the machining process by using the cutting force ratio. The previously developed surface roughness models for turning and milling proce...

The parallel-plate capacitor equation is widely used in contemporary material research for nanoscale applications and nanoelectronics. To apply this equation, flat and smooth electrodes are assumed for a capacitor. This essential assumption is often violated for thin-film capacitors because the formation of nanoscale roughness at the electrode interface is very probable for thin films grown via...

AIM The aim of this study was to investigate the association of different degradations on the roughness, gloss, and color changes of microhybrid composites. MATERIALS AND METHODS Ten specimens were prepared for Charisma, Amelogen Plus, Point 4, and Opallis resins. Surfaces were polished and baseline measurements of roughness, gloss, and color were recorded. Specimens were then submitted to ch...

Despite the continuing efforts to improve existing soil moisture retrieval algorithms, the ability to estimate soil moisture from passive microwave observations is still hampered by problems in accurately modelling the observed microwave signal. Due to the significant influence of both soil roughness and vegetation on the measured brightness temperatures, the parameterisation of these variables...