Inverse Estimation of the Front Surface Temperature of a 3-D Finite Slab Based on the Back Surface Temperature Measured at Coarse Grids

2013 ◽  
Vol 63 (1) ◽  
pp. 1-17 ◽  
Author(s):  
Yunpeng Ren ◽  
Yuwen Zhang ◽  
J. K. Chen ◽  
Z. C. Feng
Keyword(s):  
Surface Temperature ◽  
Front Surface ◽  
Back Surface ◽  
Finite Slab ◽  
Inverse Estimation ◽  
Coarse Grids

Efficiency Enhancement of Photovoltaic/Thermal Module Using Front Surface Cooling Technique in Winter and Summer Seasons: An Experimental Investigation

2019 ◽  
Vol 141 (9) ◽  
Author(s):  
Himanshu Sainthiya ◽  
Narendra S. Beniwal
Keyword(s):  
Solar Cell ◽  
Surface Water ◽  
Surface Temperature ◽  
Front Surface ◽  
Climatic Conditions ◽  
Back Surface ◽  
Water Cooling ◽  
Performance Parameters ◽  
Surface Cooling ◽  
Overall Efficiency

This paper presents the effect of the front surface water cooling on performance parameters (solar cell temperature, back surface temperature, outlet water temperature, electrical efficiency, overall efficiency, etc.) of photovoltaic/thermal (PV/T) module in both winter and summer seasons in Indian climatic conditions. A mathematical model of PV/T module considering energy balance equations has also been presented. A comparative analysis of performance parameters obtained analytically and experimentally has also been presented. A fair agreement has also been found between analytical and experimental results which is supported by correlation coefficient of approximately unity and root mean square error of 10–14%. By front surface water cooling, solar cell and back surface temperature of PV/T module have been found to decrease considerably which in turn resulted in enhanced electrical and overall efficiency of module in winter and summer seasons.

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.

Inverse Heat Conduction in a Composite Slab With Pyrolysis Effect and Temperature-Dependent Thermophysical Properties

2009 ◽  
Author(s):  
Jianhua Zhou ◽  
Yuwen Zhang ◽  
J. K. Chen ◽  
Z. C. Feng
Keyword(s):  
Heat Flux ◽  
Heat Conduction ◽  
Surface Temperature ◽  
Thermophysical Properties ◽  
Laser Heating ◽  
Front Surface ◽  
Back Surface ◽  
Inverse Heat Conduction ◽  
Temperature Dependent ◽  
Composite Slab

The inverse heat conduction problem (IHCP) in a one-dimensional composite slab with rate-dependent pyrolysis chemical reaction and outgassing flow effects is investigated using the conjugate gradient method (CGM). The thermal properties of the composites are considered to be temperature-dependent, which makes the IHCP a nonlinear problem. The inverse problem is formulated in such a way that the front-surface heat flux is chosen as the unknown function to be recovered, and the front-surface temperature is computed as a by-product of the IHCP algorithm, which uses back-surface temperature and heat flux measurements. The proposed IHCP formulation is then applied to solve the IHCP in an organic composite slab whose front surface is subjected to high intensity periodic laser heating. It is shown that an extra temperature sensor located at an interior position is necessary since the organic composites usually possess a very low thermal conductivity. It is also found that the frequency of the periodic laser heating flux plays a dominant role in the inverse solution accuracy. In addition, the robustness of the proposed algorithm is demonstrated by its capability in handling the case of thermophysical properties with random errors.

scholarly journals Effect of Surface Roughness on Ultrasonic Testing of Back-Surface Micro-Cracks

2018 ◽  
Vol 8 (8) ◽  
pp. 1233 ◽  
Author(s):  
Zhe Wang ◽  
Ximing Cui ◽  
Hongbao Ma ◽  
Yihua Kang ◽  
Zhiyang Deng
Keyword(s):  
Surface Roughness ◽  
Ultrasonic Testing ◽  
Amplitude Ratio ◽  
Ultrasonic Inspection ◽  
Front Surface ◽  
Signal Amplitude ◽  
Back Surface ◽  
Element Analysis ◽  
Arithmetic Average ◽  
Micro Cracks

Surface roughness is one of the main factors that affect the ultrasonic testing of micro-cracks. This article theoretically analyzes the relationship between the changes in the energy intensity of crack echo waves and roughness-modified transmission coefficients. A series of simulations are carried out using two-dimensional sinusoidal curves as rough surface. Then, parallel experiments are performed on sample surfaces with different arithmetic average heights (Ra). The signal amplitude ratio factor (SARF) is defined to assess the ultrasonic detection capacity for micro-cracks. Both finite element analysis and experimental results show that signal amplitude decreases with an increase in Ra, resulting in signal-to-noise ratio loss. Amplitude attenuation caused by the rough back surface is less than that caused by the rough front surface. It is difficult to identify the signal of micro-cracks with a depth less than 400 μm when the Ra of the front surface is larger than 15 μm. Cracks with depths of more than 200 μm can be distinguished when the back-surface roughness is less than 24 μm. Furthermore, the amplitude of the micro-crack signal increases slightly with variation in the horizontal parameter (Rsm). This study provides a valuable reference for the precision evaluation of micro-cracks using ultrasonic inspection.

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