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

Abstract

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.

Hardening of Cylindrical Bars with Water Impinging Jet Quenching Technique

“…The technique has already shown its high flexibility in previous studies associated with quenching of steel plates and hollow cylinders. [ 16–21 ] The flexibility of the experiments and the knowledge of relationship between the flow rates and the quality of final products can significantly contribute to further improvements of steel production lines, specifically to reduction of unnecessary resources, such as excess quenching medium or no longer necessary alloying elements, and in this way contribute to emission reduction. Furthermore, simulation of quenching combined with the physical experiments can contribute to these improvements by providing a better understanding of the ongoing processes during quenching and reducing the experimental design time.…”

Differential Microstructure and Properties of Boron Steel Plates Obtained by Water Impinging Jet Quenching Technique

“…The test rig for IJQT was developed at the University of Gävle, Sweden, and a number of experimental and numerical investigations of the quenching process of hollow cylinders have been thoroughly investigated with the aim to improve controllability of this technique. [ 3–7 ]…”

“…The test rig for IJQT was developed at the University of Gävle, Sweden, and a number of experimental and numerical investigations of the quenching process of hollow cylinders have been thoroughly investigated with the aim to improve controllability of this technique. [3][4][5][6][7] Carbon steels containing boron are known for their high hardenability. This effect is achieved by migration of boron to austenite grain boundaries during cooling that retards the nucleation of ferrite and bainite.…”