Flow Boiling of Water in a Rectangular Metallic Microchannel

Özdemir, Mehmed Rafet; Mahmoud, Mohamed M.; Karayiannis, Tassos G.

doi:10.1080/01457632.2019.1707390

Cited by 45 publications

(26 citation statements)

References 51 publications

(95 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…They concluded that the heat transfer coefficient increases with increasing aspect ratio up to AR= 3.54 and then decreases. Özdemir et al [107] studied flow boiling of water in single copper channels of hydraulic diameter 0.56 mm, length 62 mm and AR = 0.5, 2.56 and 4.99. The authors reported that the heat transfer coefficient increased as the aspect ratio decreased up to a heat flux of approximately 500 kW/m 2 .…”

Section: Effect Of Channel Aspect Ratiomentioning

confidence: 99%

Flow Boiling in Micro-Passages: Developments in Fundamental Aspects and Applications

Karayiannis

Mahmoud

2018

International Heat Transfer Conference 16

Self Cite

View full text Add to dashboard Cite

Flow boiling in mini to micro passages located at the heat source, and as part of a thermal management system, has been identified as a possible way to remove the increasing high heat fluxes generated by high power electronic devices due to their capability of high heat transfer rates with small surface temperature variations. However, some still unresolved fundamental issues hinder the possible full adoption of this technology. These relate to the prevailing flow patterns, heat transfer rates and pressure drop in such geometries, and their dependence on key parameters. The possible major applications of flow boiling in microchannels are first mentioned in this paper, highlighting the requirements and the challenges of the thermal management of each application. The paper then presents new experimental research by the present authors as well as research reported in the literature on flow boiling in single tubes and rectangular multi microchannels to help elucidate the following fundamental issues: the definition of a microchannel, prevailing flow patterns, heat transfer mechanisms, flow instability and reversal and their effect on heat transfer rates, effect of channel material and surface characteristics (including latest research in coatings), effect of different fluid properties, and its relation to channel material, effect of channel length and aspect ratio. An appreciation of the above can help explain the interpretation of the prevailing fluid flow and heat transfer phenomena and the data scatter and discrepancies observed in past studies. In addition, models and correlations predicting flow patterns and heat transfer rates are presented.

show abstract

Section: Effect Of Channel Aspect Ratiomentioning

confidence: 99%

Flow Boiling in Micro-Passages: Developments in Fundamental Aspects and Applications

Karayiannis

Mahmoud

2018

International Heat Transfer Conference 16

Self Cite

View full text Add to dashboard Cite

show abstract

“…The experimental data utilised in this study are obtained from Özdemir's [18] experimental test setup. The data are procured from the voltage, current, mass flow rate, pressure measurements and thermocouple readings.…”

Section: Data Reductionmentioning

confidence: 99%

“…The local axial wall temperatures were measured in the 0.6 mm inner diameter and 6 mm length holes at the side of each microchannel test section. The holes were located 1.1 mm distance below the channel bottom to accommodate K-type thermocouples [18]. Relevant properties and their equations are given as follows.…”

Section: Data Reductionmentioning

confidence: 99%

See 1 more Smart Citation

Exergo-Economic Analysis of Microchannels in Single-Phase Flow

Özdemir¹

2018

Journal of Thermal Engineering

Self Cite

View full text Add to dashboard Cite

With the increase of energy demand, many researchers tried to develop scientific approaches in order to design more efficient and environmentally friendly energy systems. Exergo-economic (thermoeconomic) analysis of a system or device is an efficient tool for evaluating the system in terms of the thermodynamic and economic aspects. In this parametric study, exergo-economic analysis of rectangular copper plain microchannels under single-phase flow conditions were investigated using de-ionised water. The exergo-economic performance was evaluated based on the relative cost difference and unit cost per product exergy tools. The channel aspect ratio effect on the unit cost per product exergy and relative cost difference was examined using three microchannel test sections with the same channel hydraulic diameter (Dh = 0.56 mm) and length (L = 62 mm) but different aspect ratios (β = 0.5, 2.56 and 4.94) under single-phase flow conditions. The results showed that the exergo-economic performances of the three microchannel test sections decreased as the net heat input increased over the experimental range. Moreover, the exergo-economic performance of test section 2 (β = 4.94) was found to be greater than the exergo-economic performances of test sections 1 and 3 (β = 0.5 and 2.56) at fixed flow rate and fixed net heat input case.

show abstract

“…Kim and Sohn [10] developed a correlation for heat transfer coefficient after an experimental study of the flow boiling in a rectangular channel with large range of Reynolds number and heat flux. Özdemir et al [11] studied experimentally the flow boiling of water in single rectangular microchannels.…”

Section: Introductionmentioning

confidence: 99%

Using artificial neural network for predicting heat transfer coefficient during flow boiling in an inclined channel

et al. 2021

View full text Add to dashboard Cite

The flow and heat transfer characteristics in a nuclear power plant in the event of a serious accident are simulated by boiling water in an inclined rectangular channel. In this study an artificial neural network model was developed with the aim of predicting heat transfer coefficient (HTC) for flow boiling of water in inclined channel, the network was designed and trained by means of 520 experimental data points that were selected from within the literature. orientation ,mass flux, quality and heat flow which were employed to serve as variables of input of multiple layer perceptron (MLP) neural network, whereas the analogous HTC was selected to be its output. Via the method of trial-and-error, MLP network with 30 neurons in the hidden layer was attained as optimal ANN structure. The fact that is was enabled to predict accurately the HTC. For the training set, the mean relative absolute error (MRAE) is about 0.68 % and the correlation coefficient (R) is about 0.9997. As for the testing and validation set they are respectively about 0.60 % and 0.9998 and about 0.79 % and 0.9996. The comparison of the developed ANN model with experimental data and empirical correlations in vertical channel under the low flow rate and low quality shows a good agreement.

show abstract

Flow Boiling of Water in a Rectangular Metallic Microchannel

Cited by 45 publications

References 51 publications

Flow Boiling in Micro-Passages: Developments in Fundamental Aspects and Applications

Flow Boiling in Micro-Passages: Developments in Fundamental Aspects and Applications

Exergo-Economic Analysis of Microchannels in Single-Phase Flow

Using artificial neural network for predicting heat transfer coefficient during flow boiling in an inclined channel

Contact Info

Product

Resources

About