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Abstract
The heat transfer and fluid flow due to the impingement of vertical circular jet on a horizontal heated surface is investigated numerically and experimentally for single jet and experimentally only for multi jets of four arrangcments, double jct. three in line, L-shaped and full cluster, in order tu study the cfTcct of interactiun between jets on heat transfer.
A mathematical model is driven for single jet and executed by a computer program, which is prepared for that purpose. The numerical results are presented for range of Reynolds number between 1000 and 40000, showing the variation of both segment and average segment Nusselt numbers as well as the velocity and temperature distribution in the film region. These limits cover the engineering and industrial applications.
An experimental apparatus was designed to measure the film thickness distribution, wall temperature and mean temperature of flowing fluid, in urder to calculate the segment and average segment Nusselt numbers. Six-volume flow rates are used I, 2, 4, 5, 6, and 8 liter/minute for single jet for the purpose of comparison with the numerical results. The volume flow rates I, 5 and 8 liter/minute per jet is used for multi jets.
A comparison between experimental and numerical results for single jet IS carried out; it was observed that there is a good agreement between them.
From the data obtained either numerically or experimentally it was observed that for all Reynolds number that both segment and average segment Nusselt numbers are reduced with increasing radius ratio especially in the shooting flow region through which they are reduced sharply.
Final1y, comparisons between single and multiple jets in different situation were carried out. The comparisons show that, in case of multi jets an interaction appeared between the jets. The effect of interaction between jets in multi jets tend to reduce both seh’lnent and average segment Nusselt numbers for one jet of the multi jets compared with single jet in the jump area. But the overal1 average Nusselt number on the plate area for multi jets for any arrangement is higher than single jet with the same flow rate. To reduce the effect of interaction between the jets, it is required to increase nozzle-to-nozzle separating distance. This thesis contains seven chapters. The first chapter is for introduction and review for the previous work, the second for description of the experimental apparatus, the third for derivation of mathematical model for single jet, the fourth is for test procedures and data reduction, the fifth is the discussion of the numerical results obtained, the sixth contains the presentation of experimental results and their discussion and finally comparisons between single and multi jets. The last chapter is the conclusion and recommendation for the future work.