基于组态软件的热管传热性能检测系统

以热管传热性能检测综合系统为例,介绍了利用国产工控组态软件—组态王设计其上位机检测系统。实践证明,系统图形界面友好、运行稳定、操作方便,提高了工作效率。

热管技术在液压系统中的应用研究

热管是一种超导热体的传热元件,具有传热系数高、温度分布均匀、热响应迅速、结构紧凑、工作可靠等优点。本文主要介绍了热管的工作原理及结构,重点阐述了热管式散热器在液压领域中的应用,并做了性能分析与研究,对热管在液压领域里的应用进行了展望。

Analysis of Heat Transfer Performance of Oscillating Heat Pipes Based on a Central Composite Design

Oscillating heat pipes (OHPs) are very promising cooling devices. Their heat transfer performance is af- fected by many factors, and the form of the relationship between the performance and the factors is complex and non-linear. In this paper, the effects of charging ratio, inclination angle, and heat input and their interaction effects on heat transfer performance of a looped copper-water OHP are analyzed. First, suppose that the relationship between the response and the variables approximates a second-order model. And use the central composite design to arrange the ex- periment. Then, the method of least squares is used to estimate the parameters in the second-order model. Finally, multi- variate variance analysis is used to analyze the model. The results show that the assumption is right, that is to say, the re- lationship is well modeled by a second-order function. Among the three main effect variables, the effect of inclination angle is the most significant, but their interaction effects are not significant. In the range of the considered factors, both the optimum charging ratio and the optimum inclination angle increase as the heating water flow rate increases.

Thermal Characteristics of Heat Pipe with Axially Swallow-tailed Microgrooves

A thermal model for a heat pipe with axially swallow-tailed microgrooves is developed and analyzed numerically to predict the heat transfer capacity and total thermal resistance.The effect of heat load on the axial distribution of capillary radius,and the effect of working temperature and wick structure on the maximum heat transfer capability,as well as the effect of the heat load and working temperature on the total thermal resistance are all investigated and discussed.It is indicated that the meniscus radius increases non-linearly and slowly at the evaporator and adiabatic section along the axial direction,while increasing drastically at the beginning of the condenser section.The pressure difference in the vapor phase along the axial direction is much smaller than that in the liquid phase.In addition,the heat transfer capacity is deeply affected by the working temperature and the size of the wick.A groove wick structure with a wider groove base width and higher groove depth can enhance the heat transfer capability.The effect of the working temperature on the total thermal resistance is insignificant;however,the total thermal resistance shows dependence upon the heat load.In addition,the accuracy of the model is also verified by the experiment in this paper.

A comprehensive comparison on vibration and heat transfer of two elastic heat transfer tube bundles

Elastic heat transfer tube bundles are widely used in the field of flow-induced vibration heat transfer enhancement. Two types of mainly used tube bundles, the planar elastic tube bundle and the conical spiral tube bundle were comprehensively compared in the condition of the same shell side diameter. The natural mode characteristics, the effect of fluid-structure interaction, the stress distribution, the comprehensive heat transfer performance and the secondary fluid flow of the two elastic tube bundles were all concluded and compared. The results show that the natural frequency and the critical velocity of vibration buckling of the planar elastic tube bundle are larger than those of the conical spiral tube bundle, while the stress distribution and the comprehensive heat transfer performance of the conical spiral tube bundle are relatively better.

Heat Transfer Properties and Chaotic Analysis of Parallel Type Pulsating Heat Pipe

The refrigerant mixture of ethanol aqueous was applied to the parallel type pulsating heat pipe (PHP). The operation characteristics of the PHP were analyzed by means of experiment and nonlinear chaotic theory. Moreover, the relationship between the running state and attractor was described. The results indicate that starting power, stable running power and dry burning transition power are about 64.08 W, 148.68 W and 234.0 W respectively. The cycle and amplitude of PHP initially decrease and then increase with the increasing power. However, the data are welldistributed in a certain range. The running state is in agreement with the attractors, and the changing process for attractors is as follows: the attractors first disperse in the whole phase space, then present mass status, and finally show band distribution.

Experimental investigation of thermal performance characteristics of sintered copper wicked and grooved heat pipes:A comparative study

Heat pipes are most frequently used for thermal management solutions.Selection of right type of heat pipe for a specific scenario is utmost necessary for best outcomes.The purpose of this research is comparison of thermal performance characteristics of sintered copper wicked and grooved heat pipes,which are mostly used types of heat pipes.Distilled water filled heat pipes were tested through experimentation in gravity assisted position.Experimental outcomes have been compiled in terms of capillary pressure,operating temperature,thermal resistance and heat transfer coefficient.Capillary pressure is high in sintered heat pipes compared to grooved heat pipes irrespective of groove dimensions.Grooved heat pipes have lower operating temperature compared to sintered heat pipes at the same heat load.At 8 W,compared to sintered heat pipes,grooved heat pipes have 8.24% lower condenser surface temperature,4.41% lower evaporator surface temperature and 7.79% lower saturation temperature.Thermal resistance of sintered heat pipe is much lower than grooved heat pipe.The maximum relative difference of 63.8% was observed at 8 W.Heat transfer coefficient of sintered heat pipe was observed double compared to grooved heat pipe at 8 W heat load.Thermal resistance and hence heat transfer coefficient of sintered heat pipe change almost in a linear manner with respect to heat load but unexpectedly turning point is observed in thermal resistance and heat transfer coefficient of grooved heat pipe.Grooved heat pipes attain equilibrium much earlier compared to sintered ones.Varying heat loads from 4 to 20 W causes variation in equilibrium establishment time from 7 to 4 min for grooved and from 10 to 7 min for sintered heat pipes.

Study on Heat Dissipater for High-Power Thyristors in Explosion-Proof Shell

A new type water-cooled heat dissipater for multiple high-power thyristors in explosion-proof shell used in coal mine was designed, and then, the numerical computation of the three-dimensional steady-state temperature distributions under different working conditions for cooling core was conducted in order to understand in detail the heat transfer performance. Based on the computation results, the temperature differences and the maximum heat transfer rates were given. These results of the study on the heat dissipater lay a basis for optimising its structure design and guiding its operation.

Function chain neural network prediction on heat transfer performance of oscillating heat pipe based on grey relational analysis

As for the factors affecting the heat transfer performance of complex and nonlinear oscillating heat pipe (OHP),grey relational analysis (GRA) was used to deal with the relationship between heat transfer rate of a looped copper-water OHP and charging ratio,inner diameter,inclination angel,heat input,number of turns,and the main influencing factors were defined.Then,forecasting model was obtained by using main influencing factors (such as charging ratio,interior diameter,and inclination angel) as the inputs of function chain neural network.The results show that the relative average error between the predicted and actual value is 4%,which illustrates that the function chain neural network can be applied to predict the performance of OHP accurately.

Testing Thermal Properties of Cooling Device with Heat Pipes to Improve His Heat Transfer Ability

This paper deals about testing thermal properties of the cooling device with heat pipes at inclination position, in consequence of using the natural convection to improve heat transfer properties. Head point testing of cooling device is monitoring temperature on the aluminium block of energy converter, heat pipes and ribs under temperature condition 30 ℃ in thermostatic chamber. Testing of the device was performed at tilt angles positions 0, 10 and 20° from the vertical level. The heat flux loaded to energy converter was 450 W. The next goal of the paper is to research on influence working position of the wick heat pipe on their thermal performance. In this research heat pipes were made with capillary structure sintered from copper powder granularity 100, 63 and 50 μm filled with water and ethanol. Next heat pipe thermal performance was performed by measuring heat source and working positions. Knowledge of these two research goals can bring potential improvements in purpose of cooling device for effective heat sink from high power electronic components.

Heat Transfer Performance of a Multi-heat Pipe Using Graphene Oxide/Water Nanofluid

A multi-heat pipe is a device for heat transmission. It is composed of a heating section, a cooling section and an adiabatic section. The heating and cooling sections are the same and both are connected by four circular parallel tubes. This experimental study is performed to investigate heat transfer performance of a multi-heat pipe in the vertical orientation using pure water and GO （graphene oxide）/water nanofluid. GO/water nanofluids were synthesized by the modified Hummers method with 0.05%, 0.1%, 0.15%, and 0.2% volume concentrations. The thermal performance has been investigated with varying heat flux in the range of 10-30 W and 100% fill charge ratio. Wall temperature, thermal resistance, and heat transfer coefficient of the heat pipe are measured and compared with those for the heat pipe using pure water. The experimental results show that the evaporator wall temperature with GO nanofluid is lower than that of the base fluid. Also, the heat pipe that charged with nanofluids showed lower thermal resistance compared with pure water. Heat transfer enhancement is caused by suspended nanoparticles and is pronounced with the increase in particle volume fraction.

Experimental Study on Heat Transfer Performance of Pulsating Heat Pipe with Refrigerants

The effects of different refrigerants on heat transfer performance of pulsating heat pipe(PHP) are investigated experimentally.The working temperature of pulsating heat pipe is kept in the range of 20℃-50℃.The startup time of the pulsating heat pipe with refrigerants can be shorter than 4 min,when heating power is in the range of 10W-100W.The startup time decreases with heating power.Thermal resistances of PHP with filling ratio 20.55% were obviously larger than those with other filling ratios.Thermal resistance of the PHP with R134a is much smaller than that with R404A and R600a.It indicates that the heat transfer ability of R134a is better.In addition,a correlation to predict thermal resistance of PHP with refrigerants was suggested.

Experimental Study of the Airside Performance for Interrupted Fin-and-tube Heat Exchanger with Hydrophilic Coating under Dehumidifying Conditions

The airside heat transfer and friction characteristics of seven interrupted fin-and-tube heat exchangers with hydrophilic coating under dehumidifying conditions are experimented.The effects of number of tube rows,fin pitch and inlet relative humidity on airside performance are analyzed.The test results show that the influence of fin pitch on the friction characteristic under dehumidifying conditions is similar to that under dry surface,and the friction factors decrease slightly with the increase of number of tube rows.The heat transfer performance decreases as fin pitch and number of tube rows increases.The heat transfer performance and the friction characteristic are independent of inlet relative humidity.Based on the test results,heat transfer and friction correlations in terms of the Colburn j factor and Fanning f factor,are proposed to describe the airside performance of the interrupted fin geometry with hydrophilic coating under dehumidifying conditions.The correlation of the Colburn j factor gives a mean deviation of 9.7%,while the correlation of the Fanning f factor shows a mean deviation of 7.3%.