Experimental and modelling aspects of flow boiling heat transfer for application to internal combustion engines

Robinson, Kevin; Hawley, J G; Campbell, N A F

doi:10.1243/095440703769683289

Cited by 35 publications

(22 citation statements)

References 21 publications

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“…engine on subcooled flow boiling for a 50-50 ethylene glycol-water mixture [25], their results suggesting that a correction factor is required only on the forced convection component, consistently with [20]. However, it was already noted by [20] that the model fails in the boiling regime for low velocities and low inlet temperatures.…”

Section: Introductionmentioning

confidence: 59%

“…These models are attractive mainly because the correct asymptotes are provided at the transition to the nonboiling regime, where the nucleate boiling component vanishes and only the convective component remains. In the particular case of n = 1 one recovers the simple additive model first proposed by Chen [19], which has been used almost exclusively in the automotive literature [20,14], even if its application to engine cooling passages is not totally straightforward, as the definition of a hydraulic diameter is not obvious [21].…”

Section: Introductionmentioning

confidence: 99%

“…The most comprehensive analysis of the application of the Chen model to internal combustion engines is probably that presented by Robinson et al [20]. They stressed the importance of an accurate representation of the purely convective heat transfer accounting for the complex issues associated with the fact that the flow is undeveloped both hydrodynamically and thermally, for the sensitivity to temperature of the fluid viscosity and for surface roughness [22].…”

Section: Introductionmentioning

confidence: 99%

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Experiments on subcooled flow boiling in I.C. engine-like conditions at low flow velocities

Torregrosa

Broatch

Olmeda

et al. 2014

Experimental Thermal and Fluid Science

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Subcooled boiling flow is specially attractive for engine cooling system design, as no essential changes in its architecture are required while it is still possible to take advantage of the highest rates of heat transfer associated with nucleate boiling, mostly at high engine loads. In this paper, experiments on subcooled boiling flow in representative temperature conditions were conducted with a usual engine coolant in the low velocity range, for which little information is available, even if it may be relevant when advanced thermal management strategies are used. The results were analyzed by comparison with a reference Chen-type model which provided reasonable results for relatively low wall temperatures, but with noticeable discrepancies at higher wall temperatures. Analysis of the deviations observed indicated a significant influence of the Prandtl number on the suppression factor, and the inclusion into the model of a first estimate of this effect produced a noticeable improvement in its results, thus suggesting that one such modified additive model may be useful for practical engine cooling applications.

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Section: Introductionmentioning

confidence: 59%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Experiments on subcooled flow boiling in I.C. engine-like conditions at low flow velocities

Torregrosa

Broatch

Olmeda

et al. 2014

Experimental Thermal and Fluid Science

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“…According to the literature, there are several other experimental setups with different geometries; although in those cases, where the field of application is the automotive industry, a small, flat plate is normally used. For these experiments, a 25 mm high by 20 mm wide rectangular section was chosen, similar to the experiments of Robinson et al [13], Steiner et al [11], Klausner et al [14], or Maurus et al [15]. An up to 2 MW/m 2 heat flux was introduced into the channel by a small boiling surface that is in contact with an electrically heated copper block that is located at the bottom of the duct.…”

Section: Resultsmentioning

confidence: 99%

Implementation of a nucleate boiling flux partitioning model for a CFD simulation of compact heat exchangers based on the local estimation of bulk properties

Paz¹,

Porteiro²,

Copo³

et al. 2014

Advances in Fluid Mechanics X

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The widely used implementation of wall heat flux partitioning during subcooled flow nucleate boiling has a number of limitations when it is applied on a local cell basis as is done in CFD codes. The main limitations reported generally have their origin in the bulk formulation of the proposed submodels being transferred to a local balance at the cell near the wall whose volume and flow conditions strongly differ from those employed in the experimental calibration of the model imposed. Several models developed for nucleate boiling are based on a so-called wall heat flux partitioning strategy that consists of a modification of the convective heat transfer law at the wall to include evaporation. However, it is known that the local movement of the subcooled liquid to replace the volume of vapour represents an enormous contribution to heat flux enhancement, a process that is known as quenching. Therefore, when a 3D, local formulation of a wall heat flux partitioning boiling submodel is implemented at the cell scale in a CFD code, it must take into account that most of the available correlations and the physical phenomenon itself are strongly connected with regions of the fluid that are quite distant from the wall, normally around 0.5 mm. The numerical structure of CFD codes is not suitable for a non-local formulation. Therefore, this study attempts to address these limitations to implement a flux partitioning boiling model at the local cell scale but employs distant properties of the fluid for bulk conditions and heat exchange. This method has been validated in several geometries, allowing parallelisation and full grid size and shape versatility. Advances in Fluid Mechanics X 27 realistic. Moreover, it could also be used in any physical model that requires the value of certain properties at some reference distance from the wall.

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“…For these experiments a 25mm high and 20mm wide rectangular section for the duct, similar to that used in et al and Robinson et al experiments, was chosen [4,6]. 355mm long piece was also added in order to ensure a developed flow before the heated wall duct.…”

Section: Methodsmentioning

confidence: 99%

CFD implementation and experimental validation of the Chen model for heat transfer in nucleate boiling

Paz

Suárez

Concheiro

et al. 2013

Computational Methods in Multiphase Flow VII

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The present paper describes a nucleate boiling model based on Chen's correlation, and posterior validation with experimental data. When using a heat exchanger with a liquid coolant, if the wall exceeds the saturation temperature of the liquid at system's pressure, it may boil, increasing the heat transfer law. The aim of this study is to validate the model developed with some experiments carried out in a heated flat probe. The proposed algorithm consists of a heat flux partition in two terms, one regarding the forced convection heat transfer existing in the free-boil area, and the other term considers the heat transfer increment due to the nucleate boiling. Consequently, general results show lower temperatures in the wall because of the increased heat flux, proved in several industrial components within these conditions. To achieve the model validation, some simulations were developed with the CFD software Ansys Fluent, configured with the same geometry and conditions as our experimental installation. Using a copper conduction, a heat flux up to 2MW is used to increase the temperature of a wall in contact with water, which flows through a 20mm wide and 25mm high duct. Heat transfer data are recorded while the temperature increases, allowing us to compare the boiling curves with the CFD boiling model results. Data comparisons show a good agreement with five cases studied at different conditions of system pressure and velocity and temperature inlet. An implementation of a widely used boiling model has been developed and its results have been validated with our experimental data, providing a good agreement under the specified conditions. The obtained results have shown an important improvement with respect to other multiphasic and standard models, offering better results simulating industrial components.

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Experimental and modelling aspects of flow boiling heat transfer for application to internal combustion engines

Cited by 35 publications

References 21 publications

Experiments on subcooled flow boiling in I.C. engine-like conditions at low flow velocities

Experiments on subcooled flow boiling in I.C. engine-like conditions at low flow velocities

Implementation of a nucleate boiling flux partitioning model for a CFD simulation of compact heat exchangers based on the local estimation of bulk properties

CFD implementation and experimental validation of the Chen model for heat transfer in nucleate boiling

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