الفهرس 
CHAPTER 1: INTRODUCTIONOnly 14 pages are availabe for public view
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Abstract
This research is to study the heat transfer characteristics of
jet impinging hot circular cylinder. Cooling is designated to be
under single and triple jets. The effects of initial specimen
temperature, cooling water temperature, jet velocity, and jet
diameter and jet height are examined.
Experimental and numerical investigations have been
conducted for quenching of a hot cylinder with initial
temperature of 300 to 400 oC by a subcooled water jet. Water is
injected perpendicularly on cylinder circumference via a round
jet. Jet diameters of 3 and 4mm are examined. Injected water
temperature is controlled to cover range of subcooling from
20oC to 60oC.
An original experimental device allowing the
measurements of metal temperature variation with time inside
the specimen is used. The distance between the jet and outer
cylinder surface is 5 and 10cm. The water velocities are 4 to
8m/s. A numerical model is used to verify the experiments
results. Heat fluxes and surface heat transfer coefficients are
represented. In reference to the results, the transition from film
boiling to nucleate appears clearly, before reaching the forced
convection stage.
The present work is focused on studying the parameters
that affect the cooling rate of cylindrical steel specimens, and
thus affect the steel hardness. As coming in next chapters, the
effect of initial surface temperature, water flow rate, number of
jets and water temperature will be examined. The study
quantifies the effect of changing