Heat Transfer from Studded Cylinders to a Fluid in Cross-Flow.

This research is a study of the heat transfer characteristics of cylinders with studs having constant circular cross-section and arranged in a staggered formation on the cylinder. The cylinders were placed normal to the air flow in a calibrated wind tunnel. The studs were soldered to the cylinder as a result of an initial experiment carried out to determine the merits of screwed and soldered studs. It is verified that, if the studs are not an integral part of the cylinder, there exists a resistance to heat flow at the cylinder-stud junction. Main heat transfer runs showed that as far as overall coefficient of heat transfer was concerned the length of the stud was of no consequence. A heat-transfer correlation for this case is suggested. The effect of the turbulent incident stream on heat transfer coefficient is discussed and the results of the tests conducted in the environments of the violent accoustic disturbance are presented. All the thermal runs were repeated using a plain cylinder. The variation of the heat transfer coefficient with the angular displacement of the stud from the forward stagnation point is discussed and a correlation connecting air velocity, angular position of the stud and the heat transfer coefficient is presented. This is followed by the heat transfer and pressure drop runs carried out on a studded and a plain cylinder assembly in which the width of the side walls was varied. A correlation to predict heat transfer coefficient from pressure drop measurements is suggested and verified using the results of this series of tests