A Methodology of Predicting Cavity Geometry Based on Scanned Surface Temperature Data—Prescribed Surface Temperature at the Cavity Side

1980 ◽  
Vol 102 (2) ◽  
pp. 324-329 ◽  
Author(s):  
C. K. Hsieh ◽  
K. C. Su
Keyword(s):  
Surface Temperature ◽  
Three Dimensional ◽  
Mesh Size ◽  
Front Surface ◽  
Temperature Data ◽  
Cavity Wall ◽  
Back Surface ◽  
Measured Temperature ◽  
Surface Temperature Data ◽  
Wall Position

The scanned surface temperature data from a body are used to predict the cavity lying underneath the surface. The basic system under investigation is a plane wall having a rectangular cavity at the back surface. The front surface dissipates heat by convection; this is also the surface whose temperature is scanned. For a prescribed surface temperature specified on the cavity side, a numerical solution is found convenient to predict the cavity top and the approximate location of the cavity wall. A recheck of the cavity wall position calls for matching the recalculated surface temperature with the measured temperature. The data are found to be well behaved to the extent that an interpolation is possible when the mesh size chosen happens to miss the wall position. The methodology can also be extended to prediction of holes in a three-dimensional body.

A Methodology of Predicting Cavity Geometry Based on the Scanned Surface Temperature Data—Prescribed Heat Flux at the Cavity Side

1981 ◽  
Vol 103 (1) ◽  
pp. 42-46 ◽  
Author(s):  
C. K. Hsieh ◽  
K. C. Su
Keyword(s):  
Heat Flux ◽  
Analytical Procedure ◽  
Three Dimensional ◽  
Constant Heat Flux ◽  
Temperature Data ◽  
Cavity Surface ◽  
Constant Heat ◽  
Cavity Depth ◽  
Surface Temperature Data ◽  
Wall Position

A methodology is developed to predict a rectangular cavity lying underneath the surface of a plane wall that dissipates heat by convection to the surroundings. This is also the surface whose temperature is scanned. For a prescribed constant heat flux applying on the cavity surface the cavity depth can be predicted by equating the heat in and out of the system. An analytical procedure is developed that permits checking of the assumed cavity wall position based on comparison between the calculated and the measured surface temperatures. The method is also extended to the prediction of holes in a three-dimensional body (parallelepiped). Examples are provided to illustrate applications.

High-output diesel engine heat transfer: Part 1 - comparison between piston heat flux and global energy balance

2021 ◽  
pp. 146808742110170
Author(s):  
Eric Gingrich ◽  
Michael Tess ◽  
Vamshi Korivi ◽  
Jaal Ghandhi
Keyword(s):  
Heat Transfer ◽  
Heat Flux ◽  
Diesel Engine ◽  
Surface Temperature ◽  
Fast Response ◽  
Temperature Data ◽  
Start Of Injection ◽  
Local Measurements ◽  
Surface Temperature Data ◽  
High Output

High-output diesel engine heat transfer measurements are presented in this paper, which is the first of a two-part series of papers. Local piston heat transfer, based on fast-response piston surface temperature data, is compared to global engine heat transfer based on thermodynamic data. A single-cylinder research engine was operated at multiple conditions, including very high-output cases – 30 bar IMEPg and 250 bar in-cylinder pressure. A wireless telemetry system was used to acquire fast-response piston surface temperature data, from which heat flux was calculated. An interpolation and averaging procedure was developed and a method to recover the steady-state portion of the heat flux based on the in-cylinder thermodynamic state was applied. The local measurements were spatially integrated to find total heat transfer, which was found to agree well with the global thermodynamic measurements. A delayed onset of the rise of spatially averaged heat flux was observed for later start of injection timings. The dataset is internally consistent, for example, the local measurements match the global values, which makes it well suited for heat transfer correlation development; this development is pursued in the second part of this paper.

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