%0 Journal Article %A Sozbir, Nedim %A Yao, Shi-Chune %D 2004 %I Begell House %N 3 %P 20 %R 10.1615/AtomizSpr.v14.i3.10 %T EXPERIMENTAL INVESTIGATION OF WATER MIST COOLING FOR GLASS TEMPERING %U https://www.dl.begellhouse.com/journals/6a7c7e10642258cc,1a3536ab07ef4f94,787eba0445ca1185.html %V 14 %X High-velocity air jet impingement has been applied during the cooling process of glass tempering. In order to reduce the usage of high-pressure air in the process, it is intended to demonstrate the feasibility of using water mist to enhance the air cooling. The multiple jet experiments were performed using air jet velocities between 40 and 90 m/s containing low mass flux of water mist that was varied from 0 up to 0.145 kg/m2 s for each jet. The experiments include different glass thicknesses. The optimal tempering conditions were explored.
The mechanisms of mist cooling are revealed from the experiments of a single water mist jet impinging on hot stainless steel plates. Since the droplets are small, of the order of 22 μm, heat transfer distribution of the water mist has a similar form as the air jet cooling. The total heat transfer coefficient can be viewed as two separable effects: the summation of the heat transfer coefficient of the convective air and of the impinging water flux, respectively. The heat transfer of multiple water mist jets on larger glass is studied. The mist cooling demonstrates a define saving in the use of high-pressure air. When using mist cooling, the energy requirements of the system are significantly lowered. The mist cooling creates more refined fracturing in the punching tests of tempered glass. For glass thicker than 3 mm, the particle counts due to water mist improve about 121%. The improvement is about 38% for 2-mm glass. The test results indicate that thin and low-cost tempered glass can be made by mist cooling without fracture and with about 29% air pressure reduction for 2-mm glass plate and 50% reduction for both 3-mm and 4-mm glass plates. %8 2004-06-01