Experimental Study on Enhancement Of Thermal Performance Of Wire Wound Tube In Tube Helical Coil Heat Exchanger

摘要

Present work experimentally investigates the hydrodynamic and heat transfer analysis of three different geometries of the tube in tube helical coil. This study was conducted over a range of Rey nolds numbers from 2500 to 6700 using cold water in annulus side. The experiments were carried out in counter flow configuration w ith hot water in tube side and cold water in annulus side. Each patterned coils were fabricated by bending 3.5 m straight mild steel tube having 10 mm ID and 12 mm OD, and stainless steel tube having 23 mm ID and 25 mm OD in four active helical turns having zero pitch with coil diameter 270 mm. The mild steel wires of 1.5 mm were wound on outer side of inner tube having 6 mm and 10 mm pitch distance. The annulus side Nusselt number and friction factor were determined. The pressure drop and overall heat transfer coefficient is calculated at annulus side for different rate conditions. The results show that the 6 mm wire wound tube in tube helical coil have more overall heat transfer coefficient than that of 10 mm and plain tube helical coil