Proposed models, ongoing experiments, and latest numerical simulations of microchannel two-phase flow boiling

Szczukiewicz, Sylwia; Magnini, Mirco; Thome, John R.

doi:10.1016/j.ijmultiphaseflow.2013.10.014

Cited by 124 publications

(42 citation statements)

References 89 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…This would allow the actual heat-flux distribution at the solidefluid interface to be obtained from the solution of the wall conduction equation, solved in three dimensions with measured boundary conditions. Such a possibly could be realised by using infra-red camera temperature measurement techniques, as suggested by Szczukiewicz et al [3].…”

Section: Discussionmentioning

confidence: 99%

“…McNeil et al [2] produced similar results for water and R113 boiling on a pin-fin surface. Szczukiewicz et al [3] reported on work carried out with infra red cameras that measured wall temperature distributions on surfaces heated by a uniform heat flux. They also found that subcooled liquid at heat sink inlets caused a heat flux distortion that required conduction in the substrate to be taken into account in the analysis of the data.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

The effect of substrate conduction on boiling data on pin-fin heat sinks

McNeil

Raeisi

Kew

et al. 2015

Applied Thermal Engineering

View full text Add to dashboard Cite

Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

The effect of substrate conduction on boiling data on pin-fin heat sinks

McNeil

Raeisi

Kew

et al. 2015

Applied Thermal Engineering

View full text Add to dashboard Cite

“…Several models to describe these interactions have been developed at the macroscale. As reported in Szczukiewics et al [40], several computational studies [4,41,42] have studied the growth of moving bubbles in microchannels. Due to the challenges involved with decoupling the advective and phase change heat transfer processes as well as the convection-conduction conjugate effects, the availability experimental data is rather limited.…”

Section: Bubbly Flowmentioning

confidence: 94%

Spatiotemporally resolved heat transfer measurements for flow boiling in microchannels

Rao

Peles

2015

International Journal of Heat and Mass Transfer

View full text Add to dashboard Cite

a b s t r a c tSpatiotemporally resolved wall heat transfer measurements can provide valuable insight into the fundamental mechanisms affecting flow boiling in microchannels. Operating at the microscale, necessitates resolving changes in local and instantaneous heat transfer characteristics on the order of 100 lm and 1 kHz, respectively. Straightforward interpretation of transient temperature measurements is often challenging due to the conjugate conduction effects in the substrate, which can dampen the measured and inferred heat transfer quantities. These damping effects are described using a slip coefficient (S), which represents the fraction of the change in the local heat transfer that is registered by a sensor (negligible thermal mass) located on a given substrate. Using S, arguments are presented that the conduction patterns in the substrate are predominantly 1-D (i.e. into the substrate) at suitable spatiotemporal-scales. Building on these fundamental considerations, a numerical procedure is adopted to allow a time varying estimate of the local convective heat flux and heat transfer coefficient from transient temperature measurements. Examples of this framework are showcased with experimental results and discussions for interactions observed during flow boiling of HFE 7000 in a single microchannel (hydraulic diameter = 370 lm). At the relatively low mass flux of 200 kg/m 2 s reported in this work, liquid evaporation was found to dictate the local heat transfer trends. High rates of heat transfer were observed to accompany the growth of bubbles and evaporation of the liquid film under vapor slugs. Local dryout was routinely observed in the bubbly and slug flow regime and found to initially enhance heat transfer (i.e. at the creation and subsequent propagation of the three-phase contact line) and present near-zero heat transfer rates in the dried-out domain.

show abstract

“…Nebuloni and Thome proposed a theoretical and numerical model to predict film condensation and flow boiling heat transfer in mini and micro-channels of different internal shapes [6][7][8][9]. However, most attention was paid to the thermal resistance of cooling air, and few studies have been carried out on the anti-freezing issues of ACCs.…”

Section: Introductionmentioning

confidence: 99%

Anti-Freezing Mechanism Analysis of a Finned Flat Tube in an Air-Cooled Condenser

Guo

Cheng

et al. 2017

Energies

View full text Add to dashboard Cite

Abstract:In cold winter weather, the air-cooled condensers (ACCs) face serious freezing risks, especially with part load of the power generating unit. Therefore, it is of benefit to investigate the heat transfer process between the turbine exhaust steam and cooling air, by which the freezing mechanism of the finned tube bundles can be revealed. In this work, the flow and heat transfer models of the cooling air coupling with the circulating water, are developed and numerically simulated for the anti-freezing analysis on basis of the finned tube bundles of the condenser cell. The local air-side heat transfer coefficient, condensate film development, and non-condensable gas development are obtained and analyzed in detail. The results show that, the most freezing risk happens at the fin base due to the highest air-side cooling capacity, besides the windward velocity, ambient temperature and turbine back pressure all determine the freezing risk with the constant inlet flow rate of the non-condensable gas. Furthermore, increasing fin thickness and decreasing fan rotating speed are the most effective anti-freezing measures. Additionally, increasing turbine back pressure can also be adopted to avoid ACC freezing, however the adjustment of outlet steam-air flow is not recommended.

show abstract

Proposed models, ongoing experiments, and latest numerical simulations of microchannel two-phase flow boiling

Cited by 124 publications

References 89 publications

The effect of substrate conduction on boiling data on pin-fin heat sinks

The effect of substrate conduction on boiling data on pin-fin heat sinks

Spatiotemporally resolved heat transfer measurements for flow boiling in microchannels

Anti-Freezing Mechanism Analysis of a Finned Flat Tube in an Air-Cooled Condenser

Contact Info

Product

Resources

About