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The housing of totally enclosed fan-cooled electrical machines is usually finned to maximize the heat dissipation over its surface. Complex models involving heat and fluid flow simultaneously are necessary to evaluate a single design. An optimization over a wide parameter range is, therefore, not possible. In this paper, a novel approach on how to model this particular conjugate heat transfer problem...
Experimental research of heat transfer and resistance characteristic of three sizes of corrugated tube and straight tube was done. The results show that the shape of the corrugated pipe enhances disturbance of liquid, and strengthens heat exchange ability of corrugated tube. Corrugated tube heat exchange ability increases while the ratio of corrugation pitch and external diameter of corrugated tube...
This work consists of analyzing and simulating a parabolic trough collector in order to bring out the evolution of its thermal performances, mainly the heat transfer fluid outlet temperature, the useful power and the thermal efficiency, and this under weather conditions of Errachidia region, located at the Southeast of MOROCCO. The capturing system collects energy using water as a heat transfer fluid,...
The paper presents methods for determining similarity numbers do define the density of heat flux in a system. An installation was analysed with photovoltaic tiles located on the roof of a building. The values of similarity numbers and heat flux were determined, and the type of the system was defined for the case analysed.
Pasteurization engine uses a heat exchanger to heat the milk up to 71.6 °C. Therefore, the suitable type of controller for pasteurization process must be obtained. In this paper, there are five types of controller to be compared. These controllers are a PID controller tuning Ziegler Nichols, PID tuning Cohen Coon, Cascade PID, Fuzzy Inference System and Adapative Neuro Fuzzy Inference System (ANFIS)...
A simplified one dimensional model for a small stratified domestic oil storage tank is used for a parametric study on the thermal gradient in the storage tank. The model is validated with experimental results and reasonably good agreement between experiment and simulation is obtained. The effects of measurable and physically adjustable parameters of the average charging flow-rate, the inlet charging...
Mass flow rate of liquid is an important parameter to be measured and controlled in a process industry. In this paper, the design of a PC based mass flow indicator has been studied using a well known temperature sensing IC AD590. The temperature sensing IC AD590 has been used as a flow sensing element and the effect of fluid temperature has been eliminated by using four identical IC units. Four IC...
The inclined jet of air is experimentally investigated with the aim of understanding thermal characteristics for cooling applications which can be used in electronics packaging applications. Entire study and evaluations are made by insertion of jet on the leading edge of a horizontal rectangular hot target plate. The jet is placed at height H from target to be cooled, and investigated for downhill...
This paper presents modeling, simulation, and experimental estimation of harvestable green energy from the vehicle's waste heat. Waste heat-flow through liquid-coolant and the exhaust gas are considered. We have developed two models, written in Matlab, to estimate energy in real-time from the coolant and exhaust. Heat power in kW is estimated as a function of mass flow rate, specific heat capacity,...
The thermal physical properties of water will be changing in the process of heat transfer. A mathematical model of flow water cooling is established by the heat transfer theory and the similarity criterion. The heat transfer medium parameters are predicted by the neural network and the system temperature difference will be considered. It implemented network training and testing through the programming...
Some of the largest heat densities that can be found in contemporary engineering applications are present in 3D chip stacks (~103 W/cm3), and micro-fluidic systems have been proposed to cool these devices. As the chip heat flux is non-homogenous, hot spots exist which require greater local heat transfer coefficients than the surrounding regions. To cool on-chip hot-spots, a passively actuated structure...
An ultra-thin polymer pulsating heat pipe (PPHP) was developed by forming with UV curable polymer resin on polyethylene terephthalate films and hydrofluoroether was used as a working fluid. The casing materials were selected in consideration of compatibility between case materials and the working fluid and also the heat and pressure durability. A new apparatus was constructed to evaluate the thermal...
In this study, as a passive energy conversion/transport device, the performance of a pulsating heat pipe (PHP) using nanofluid is experimentally investigated. It has been suggested that nanofluids could improve the performance of wickless self-sustaining heat pipes. The transparent fused quartz tubing with 3 mm diameter is used to visualize the oscillations within the adiabatic section of the pipe...
In this paper, two TGPs with monoporous sintered wick structures fabricated from spherical copper particles, are studied. The TGPs used in this study are 3″ by 5″ troughs, 4.8mm in depth, made of copper. On the back side of the trough, a 1cm2 raised section, referred to as pedestal, is used as a heater interface; pedestal is subjected to heat fluxes from 50 to 250 W/cm2 and the data is recorded when...
Immersion cooling is making a resurgence for use in server applications driven by an increase in chip densities and the need for reduction in overall data center power usage. This paper focuses on pool boiling characteristics from an array of heaters which simulate electronic chips on a vertically-oriented printed circuit board. A pool boiling study was conducted on an array of four bare die using...
The paper presents an experimental study on heat transfer and flow friction characteristics in a rectangular channel fitted with periodically rectangular V-ribs. The multiple V-rib turbulators are tested in the channel having an aspect ratio (width to height ratio), AR=10 and height, H= 30 mm, with three rib-to-channel height ratios (e/H=0.2, 0.3, and 0.4), two rib-pitch to channel-height ratios (PR=P...
Effective cooling is required in power generation, processing, and distribution to avoid failure that could occur during operations. As heat loads continue to increase, manufacturers of wind turbines are turning to improve the cooling system to remove high intensity heat loads from many active parts particularly in the generator part. Wind generators need an effective cooling system due to the large...
In this paper, a numerical study on the shape of the dryer was performed for the purpose of reducing energy used in the actual industrial dryer. We measured temperature distributions over the nozzles in the dryer according to two cases of power consumption. The measured temperatures are used as applied boundary conditions in the numerical model. In order to investigate the shape of energy efficient...
Nowadays, several tools are used to estimate the productivity of PVT components, nevertheless none of them takes into account all the factors and the losses that are involved in the energy balance of an hybrid collector system, like spectral efficiency of PV module or radiative heat exchange between PV module and sky. The aim of this work is the construction of a detailed mathematical model for the...
Si-based micro pulsating heat pipes (μPHP) charged with HFE-7100 were tested at several heating powers with two orientations, θ = 0° and 90°. The width of the channel is 0.8 mm in a μPHP having uniform channels, and 1.0 mm or 0.6 mm in the other μPHP. The depth of each channel is 0.25 mm. The overall size of each μPHP is 60 mm × 10 mm × 1.25 mm. Both visual observation and temperature response of...
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