Boiling Heat Transfer Characteristics of Vertical Water Jet Impinging on Horizontally Moving Hot Plate

Morisawa, Kenta; Nakahara, Junya; Nagata, Kouji; Fujimoto, Hitoshi; Hama, Takayuki; Takuda, Hirohiko

doi:10.2355/isijinternational.isijint-2017-383

Cited by 14 publications

(11 citation statements)

References 26 publications

(35 reference statements)

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“…These complexities of ROT cooling have to be to some degree incorporated into laboratory studies, but care has to be taken to translate these laboratory results into conclusions for ROT cooling. For example, conflicting results on cooling efficiencies for top versus bottom cooling have been reported …”

Section: Jet Impingement Boilingmentioning

confidence: 99%

Simulation of Runout Table Cooling

Guemo

Prodanovic

Militzer

2018

steel research int.

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Accelerated cooling on the runout table of hot mills has become a key technology to produce thermo‐mechanically controlled processed (TMCP) steel plates and strips. During runout table cooling austenite decomposition takes place and determines the final microstructure and, hence, the properties of the hot‐rolled steel. There is an increased tendency to produce higher strength TMCP steels with complex microstructures including bainite and martensite. To tailor these microstructures, it is required to carefully design runout table cooling paths and lower the cooling stop and coiling temperature, respectively, for producing flat products with homogeneous mechanical properties. Thus, simulation of runout table cooling is a crucial aspect of process modeling. In the present paper, the status of runout table simulation approaches is reviewed. In particular, the three boiling mechanisms of water cooling, that is, nucleate, transition, and film boiling are discussed. The development of appropriate heat transfer coefficients is rather mature for nucleate and film boiling, respectively. Modeling and controlling the transition boiling regime below the Leidenfrost temperature remains a challenge as heat extraction rates increase with decreasing steel temperature. The status of heat transfer simulations for transition boiling is thus discussed in detail. Currently, the proposed heat transfer correlations, while increasingly based on the underlying physics, still contain a number of empirical parameters that require tuning with experimental and/or mill data. The review is limited to information in the open literature while recognizing that a number of proprietary in‐house runout table cooling models exist that are developed either by equipment makers or steel companies to control accelerated cooling to lower cooling stop or coiling temperatures.

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Section: Jet Impingement Boilingmentioning

confidence: 99%

Simulation of Runout Table Cooling

Guemo

Prodanovic

Militzer

2018

steel research int.

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“…[8][9][10][11] Transient bottom cooling tests were carried out by Mozumder et al 12) and Chester et al 13) using circular jets. Morisawa et al 14) did a comparative study on top and bottom cooling of a moving plate by a single circular nozzle. Top and bottom jets are hydro-dynamically different, 5,14) and bottom jet experiments using planar nozzles have yet to be explored.…”

Section: Transient Bottom Jet Impingement Cooling Of Steelmentioning

confidence: 99%

“…Morisawa et al 14) did a comparative study on top and bottom cooling of a moving plate by a single circular nozzle. Top and bottom jets are hydro-dynamically different, 5,14) and bottom jet experiments using planar nozzles have yet to be explored.…”

Section: Transient Bottom Jet Impingement Cooling Of Steelmentioning

confidence: 99%

Transient Bottom Jet Impingement Cooling of Steel

2020

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Accelerated run-out table cooling has become a key technology that determines microstructure and resulting mechanical properties of thermo-mechanically controlled processed (TMCP) steels. The present study quantifies the heat transfer mechanisms during bottom jet cooling of a stationary steel plate with systematic pilot-scale experiments. The emphasis of the study is to quantify the effect of process parameters, i.e. jet impingement velocity, water temperature and nozzle orientation, on heat extraction rates. Experimental results are described and quantitatively analyzed, adding to the database for run-out table cooling.

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“…Some of the reported important parameters are liquid subcooling [5], impinging jet diameter [6,7], single water jet flow rate [5,8], material properties of quenching surface [9], initial temperature of quenching [10] and jet-to-surface spacing [5,8]. In real conditions in the metal industry, quenching is often applied on moving hot metal product on the run-out table which introduces surface moving speed as an additional parameter [11]. This causes the wetted and wetting front (WF) region to become asymmetric by hydraulic jump in one side of wetting front region [12].…”

Section: Introductionmentioning

confidence: 99%

Quenching Hot Rotary Hollow Cylinder by 1-row and 2-row Water Impinging Jet Array

Jahedi¹,

Moshfegh²

2021

JFFHMT

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Experimental study has been carried out to investigate transient quenching of rotary hollow cylinder by subcooled water impinging jets (∆ = 55-85K) in 1-row and 2-row inline array. The flow rate of water jets varied from 2.7 to 10.9 L/min, impinging on hot rotary cylinder (=600℃) with rotation speed 10-50 rpm and different curvature ratio (/d = 12, 19 and 24). The local average and maximum boiling heat transfer at water jet's stagnation point revealed effect of studied quenching parameters and multiple jet arrays in the boiling heat transfer. The result showed among the studied parameters, jet's flow rate and curvature ratio influenced heat transfer in all the boiling regimes. Rotation speed was effective in film and transition boiling regime and strong effect of subcooling was captured in the transition boiling regime. The characteristics of maximum heat flux point in the boiling curve were found to be dependent on the studied quenching parameters as well as array of nozzles. Multiple jet arrays had effect on the spatial variation and rate of boiling heat transfer on quenching surface. The heat transfer enhancement by larger number of rows, i.e. 2row array, was studied based on two approaches of constant single jet's flow rate and array's total flow rate. The result shown better heat transfer performance is achieved by increasing number of row in the array while the total flow rate is constant. It was found that by impinging constant water flow rate into the jets, 2-row array with twice the number of impinging jets enhanced heat transfer significantly in film and transition boiling regime in combination with other quenching parameters.

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Boiling Heat Transfer Characteristics of Vertical Water Jet Impinging on Horizontally Moving Hot Plate

Cited by 14 publications

References 26 publications

Simulation of Runout Table Cooling

Simulation of Runout Table Cooling

Transient Bottom Jet Impingement Cooling of Steel

Quenching Hot Rotary Hollow Cylinder by 1-row and 2-row Water Impinging Jet Array

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