Modeling, Experiment, and Fabrication of Micro-Grooved Heat Pipes: An Update

2007 ◽  
Vol 60 (3) ◽  
pp. 107-119 ◽  
Author(s):  
Balram Suman
Keyword(s):  
Heat Pipe ◽  
Heat Pipes ◽  
Sensitivity Analyses ◽  
Experimental Investigations ◽  
Future Research ◽  
Detailed Knowledge ◽  
Additional Information ◽  
Modeling Experiment ◽  
Transient Models ◽  
Work Done

The review presents an update of the work done in the micro heat pipe research and development, with an aim to give updated detailed knowledge to individuals new to the field, as well as to those already working in this area. Presented here is a summary of the recent advances in these devices occurring since the early 1990s. The following review describes the historical development of these devices, along with a review of the steady state and the transient models, sensitivity analyses, recent experimental investigations and fabrication techniques. The critical heat input, dryout length, fill charge, various heat pipe limitations and design have also been discussed in brief. Finally, future research and areas in which additional information is required are identified and delineated. This article has 204 references.

Overview of Micro Heat Pipe Research and Development

1992 ◽  
Vol 45 (5) ◽  
pp. 175-189 ◽  
Author(s):  
G. P. Peterson
Keyword(s):  
Research And Development ◽  
Heat Pipe ◽  
Historical Development ◽  
Heat Pipes ◽  
Experimental Investigations ◽  
Numerical Techniques ◽  
Fundamental Parameters ◽  
Micro Heat Pipe ◽  
Recent Advances ◽  
Micro Heat Pipes

The concept of a micro heat pipe was first proposed in 1984. Since that time, numerous analytical and experimental investigations have been conducted to determine the fundamental parameters that govern the operation of these devices. Micro heat pipes ranging in size from 1 mm in diameter and 60 mm in length to 30 μm in diameter and 10 mm in length have been analyzed, modelled, and fabricated. The following review describes the historical development of these devices, along with the analytical and numerical techniques used to model and predict their performance and the results of several recent experimental investigations. Because of recent advances in the development of micro heat pipes fabricated as an integral part of semiconductor wafers, particular emphasis has been placed on various construction and charging methods currently under investigation.

Experimental Investigations of Radially Rotating Miniature High-Temperature Heat Pipes

2000 ◽  
Vol 123 (1) ◽  
pp. 113-119 ◽  
Author(s):  
Jian Ling ◽  
Yiding Cao ◽  
Alex P. Lopez
Keyword(s):  
Heat Transfer ◽  
High Temperature ◽  
Heat Pipe ◽  
High Speed ◽  
Thermal Conductance ◽  
Heat Pipes ◽  
Experimental Investigations ◽  
Temperature Heat ◽  
Heat Transfer Capacity ◽  
High Temperature Heat Pipe

A radially rotating miniature high-temperature heat pipe employs centrifugal force to return the condensate in the condenser section to the evaporator section. The heat pipe has a simple structure, very high effective thermal conductance and heat transfer capacity, and can work in hostile high-temperature environments. In this research, a high-speed rotating test apparatus and data acquisition system for radially rotating miniature high-temperature heat pipes are established. Extensive experimental tests on two heat pipes with different dimensions are performed, and various effects of influential parameters on the performance characteristics of the heat pipes are investigated. The ranges of the important parameters covered in the current experiments are: 470⩽ω2Za¯/g⩽1881; 47 W⩽Q⩽325W; di=1.5 and 2 mm; and 1.05×10−3m3/s⩽W⩽13.4×10−3m3/s. The experimental data prove that the radially rotating miniature high-temperature heat pipe has a high effective thermal conductance, which is 60–100 times higher than the thermal conductivity of copper, and a large heat transfer capacity that is more than 300 W. Therefore, the heat pipe appears to be feasible for cooling high-temperature gas turbine components.

scholarly journals Can neuroscience help to understand narcissism? A systematic review of an emerging field

2021 ◽  
Vol 4 ◽  
Author(s):  
Emanuel Jauk ◽  
Philipp Kanske
Keyword(s):  
Systematic Review ◽  
Stress Responses ◽  
Interpersonal Functioning ◽  
Integrative Model ◽  
Experimental Investigations ◽  
Future Research ◽  
Pathological Narcissism ◽  
Ego Threat ◽  
Self Reports ◽  
And Behavior

Abstract Narcissism is a Janusian personality construct, associated with both grandiose self-assuredness and dominance, as well as vulnerable insecurity and reactivity. Central questions of intra- and interpersonal functioning in narcissism are still a matter of debate. Neuroscience could help to understand the paradoxical patterns of experience and behavior beyond the limitations of self-reports. We provide a systematic review of 34 neuroscience studies on grandiose, vulnerable, pathological narcissism, and Narcissistic Personality Disorder (NPD), spanning experimental investigations of intra- and interpersonal mechanisms, research on neurophysiological and neuroendocrine aspects of baseline function, and brain structural correlates. While neuroscience has scarcely directly studied vulnerable narcissism, grandiose narcissism is associated with heightened vigilance to ego threat and stress responses following ego threat, as well as heightened stress indicators in baseline measures. Such responses are not commonly observed in self-reports, highlighting the potential of neuroscience to augment our understanding of self-regulatory dynamics in narcissism. Interpersonal functioning is characterized by deficits in social–affective processes. Both involve altered activity within the salience network, pointing to a double dissociation regarding the expression of narcissism and self/other oriented situational focus. Findings are summarized in an integrative model providing testable hypotheses for future research along with methodological recommendations.

scholarly journals Testing algorithm for heat transfer performance of nanofluid-filled heat pipe based on neural network

Open Physics ◽  
2020 ◽  
Vol 18 (1) ◽  
pp. 751-760
Author(s):  
Lei Lei
Keyword(s):  
Neural Network ◽  
Heat Transfer ◽  
Heat Pipe ◽  
Heat Transfer Performance ◽  
Volume Fraction ◽  
Heat Pipes ◽  
Transfer Performance ◽  
Analysis Model ◽  
Accurate Analysis ◽  
Testing Algorithm

AbstractTraditional testing algorithm based on pattern matching is impossible to effectively analyze the heat transfer performance of heat pipes filled with different concentrations of nanofluids, so the testing algorithm for heat transfer performance of a nanofluidic heat pipe based on neural network is proposed. Nanofluids are obtained by weighing, preparing, stirring, standing and shaking using dichotomy. Based on this, the heat transfer performance analysis model of the nanofluidic heat pipe based on artificial neural network is constructed, which is applied to the analysis of heat transfer performance of nanofluidic heat pipes to achieve accurate analysis. The experimental results show that the proposed algorithm can effectively analyze the heat transfer performance of heat pipes under different concentrations of nanofluids, and the heat transfer performance of heat pipes is best when the volume fraction of nanofluids is 0.15%.

The Heat Transport Capacity of Micro Heat Pipes

1998 ◽  
Vol 120 (4) ◽  
pp. 1064-1071 ◽  
Author(s):  
J. M. Ha ◽  
G. P. Peterson
Keyword(s):  
Experimental Data ◽  
Heat Pipe ◽  
Heat Transport ◽  
Heat Pipes ◽  
Original Model ◽  
Semiempirical Model ◽  
Transport Capacity ◽  
Predictive Tool ◽  
Maximum Heat ◽  
Micro Heat Pipes

The original analytical model for predicting the maximum heat transport capacity in micro heat pipes, as developed by Cotter, has been re-evaluated in light of the currently available experimental data. As is the case for most models, the original model assumed a fixed evaporator region and while it yields trends that are consistent with the experimental results, it significantly overpredicts the maximum heat transport capacity. In an effort to provide a more accurate predictive tool, a semi-empirical correlation has been developed. This modified model incorporates the effects of the temporal intrusion of the evaporating region into the adiabatic section of the heat pipe, which occurs as the heat pipe approaches dryout conditions. In so doing, the current model provides a more realistic picture of the actual physical situation. In addition to incorporating these effects, Cotter’s original expression for the liquid flow shape factor has been modified. These modifications are then incorporated into the original model and the results compared with the available experimental data. The results of this comparison indicate that the new semiempirical model significantly improves the correlation between the experimental and predicted results and more accurately represents the actual physical behavior of these devices.

Experimental investigations of flat T-shaped copper and titanium heat pipes

2021 ◽  
pp. 117454
Author(s):  
Denis A. Nesterov ◽  
Valery A. Derevyanko ◽  
Sergey B. Suntsov
Keyword(s):  
Heat Pipes ◽  
Experimental Investigations

Mistuning and Damping of a Radial Turbine Wheel. Part 1: Fundamental Analyses and Design of Intentional Mistuning Pattern

2021 ◽  
Author(s):  
Alex Nakos ◽  
Bernd Beirow ◽  
Arthur Zobel
Keyword(s):  
High Stress ◽  
Forced Response ◽  
Experimental Investigations ◽  
Detailed Knowledge ◽  
Turbine Wheel ◽  
Operation Conditions ◽  
Radial Turbine ◽  
Influence Coefficients ◽  
Modes Of Vibration ◽  
The Impact

Abstract The radial turbine impeller of an exhaust turbocharger is analyzed in view of both free vibration and forced response. Due to random blade mistuning resulting from unavoidable inaccuracies in manufacture or material inhomogeneities, localized modes of vibration may arise, which involve the risk of severely magnified blade displacements and inadmissibly high stress levels compared to the tuned counterpart. Contrary, the use of intentional mistuning (IM) has proved to be an efficient measure to mitigate the forced response. Independently, the presence of aerodynamic damping is significant with respect to limit the forced response since structural damping ratios of integrally bladed rotors typically take extremely low values. Hence, a detailed knowledge of respective damping ratios would be desirable while developing a robust rotor design. For this, far-reaching experimental investigations are carried out to determine the damping of a comparative wheel within a wide pressure range by simulating operation conditions in a pressure tank. Reduced order models are built up for designing suitable intentional mistuning patterns by using the subset of nominal system modes (SNM) approach introduced by Yang and Griffin [1], which conveniently allows for accounting both differing mistuning patterns and the impact of aeroelastic interaction by means of aerodynamic influence coefficients (AIC). Further, finite element analyses are carried out in order to identify appropriate measures how to implement intentional mistuning patterns, which are featuring only two different blade designs. In detail, the impact of specific geometric modifications on blade natural frequencies is investigated.

A Numerical Analysis of Gas Turbine Disks Incorporating Rotating Heat Pipes

2000 ◽  
Author(s):  
Y. Cao ◽  
J. Ling ◽  
R. Rivir ◽  
C. MacArthur
Keyword(s):  
Heat Pipe ◽  
Gas Turbine ◽  
Heat Pipes ◽  
High Heat ◽  
Thermal Dissipation ◽  
High Heat Flux ◽  
Heating And Cooling ◽  
Turbine Disks ◽  
Higher Temperature ◽  
Lower Temperature

Abstract Radially rotating heat pipes have been proposed for cooling gas turbine disks working at high temperatures. A disk incorporating the heat pipe would have an enhanced thermal dissipation capacity and a much lower temperature at the disk rim and dovetail surface. In this paper, extensive numerical simulations have been made for heat-pipe-cooled disks. Thermal performances are compared for the disks with and without incorporating the heat pipe at different heating and cooling conditions. The numerical results presented in this paper indicate that radially rotating heat pipes can significantly reduce the maximum and average temperatures at the disk rim and dovetail surface under a high heat flux working condition. In general, the maximum and average temperatures at the disk rim and dovetail surface could be reduced by above 250 and 150 degrees, respectively, compared to those of the disk without the heat pipe. As a result, a disk incorporating radially rotating heat pipes could alleviate temperature-related problems and allow a gas turbine to work at a much higher temperature.

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