A theoretical analysis of the systematic errors in determining the thermal characteristics of structural materials by a pulse method in a sample of finite dimensions

2009 ◽  
Vol 52 (4) ◽  
pp. 384-387 ◽  
Author(s):  
G. V. Kuznetsov ◽  
M. D. Kats
Keyword(s):  
Theoretical Analysis ◽  
Thermal Characteristics ◽  
Pulse Method ◽  
Structural Materials ◽  
Systematic Errors

scholarly journals Measurement for the Thickness of Water Droplets/Film on a Curved Surface with Digital Image Projection (DIP) Technique

Sensors ◽  
2020 ◽  
Vol 20 (8) ◽  
pp. 2409
Author(s):  
Lingwei Zeng ◽  
Hanfeng Wang ◽  
Ying Li ◽  
Xuhui He
Keyword(s):  
Theoretical Analysis ◽  
Systematic Error ◽  
Digital Image ◽  
Systematic Errors ◽  
Curved Surface ◽  
Water Droplets ◽  
Image Projection

Digital image projection (DIP) with traditional vertical calibration cannot be used for measuring the water droplets/film on a curved surface, because significant systematic error will be introduced. An improved DIP technique with normal calibration is proposed in the present paper, including the principles, operation procedures and analysis of systematic errors, which was successfully applied to measuring the water droplets/film on a curved surface. By comparing the results of laser profiler, traditional DIP, improved DIP and theoretical analysis, advantages of the present improved DIP technique are highlighted.

scholarly journals Properties of the Triangular Excitation Pulse and the 3D Heat Transfer Effects in the Excitation Pulse Method

2019 ◽  
Vol 111 ◽  
pp. 04018
Author(s):  
Arash Rasooli ◽  
Laure Itard
Keyword(s):  
Heat Transfer ◽  
Thermal Resistance ◽  
Thermal Characteristics ◽  
Pulse Method ◽  
Excitation Pulse ◽  
Time Interval ◽  
Building Stock ◽  
Response Factors ◽  
Existing Building

Concerning the high levels of energy consumption in the existing building stock, the necessity for characterization of the building envelop is a well-known issue. Accordingly, numerous methods and practices have been developed and studied to measure the thermal resistance and other thermal characteristics of the walls in-situ. In the current paper, a previously proposed method, the Excitation Pulse Method, EPM, based on the theory of thermal response factors, is further studied and investigated through simulations, to rapidly measure the thermal resistance of existing walls. A prototype is built and introduced to carry out larger number of measurements on site. The triangular pulse’s properties such as the relation between its magnitude and its time interval on its corresponding response are investigated. It is shown how changes in time interval can make the method sensitive to the number of residuals and affect its reliability. General constraints and validity domain of the method are studied. In addition, the effect of 3D heat transfer on the performance of the method is further illustrated in light and heavy constructions. It is shown in which cases it is possible to apply the method in-situ and measure the thermal resistance within a couple of hours.

Theoretical Analysis on the Thermal Characteristics of Oscillating Heat Pipe

2010 ◽  
Author(s):  
Haizhen Xian ◽  
Yongping Yang ◽  
Dengying Liu ◽  
Xiaomin Liu ◽  
Xiaoze Du
Keyword(s):  
Theoretical Analysis ◽  
Heat Pipe ◽  
Inclination Angle ◽  
Thermal Characteristics ◽  
Filling Ratio ◽  
Heating Power ◽  
Working Fluid ◽  
Oscillating Flow ◽  
Oscillating Heat Pipe ◽  
Oscillation Characteristics

Theoretical analysis on the thermal characteristics of the looped oscillating heat pipe was given to predict oscillation characteristics affected by filling ratio, inclination angle and heating power. The numerical results show that the alternative expansion and compression of vapors make the working fluid keep an oscillating flow in the heat pipe. This oscillating flow is affected by the inclination angle, filling ratio and heating power.

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