Local convection heat transfer coefficient measurement in a wavy channel with flow disturbers

The need for high performance heat exchangers has led to the development of many types of surfaces that enhance the rate of heat transfer. The simplest and most common surface configuration for a two-fluid compact heat exchanger is the plate-fin arrangement. Examples of types of plate-fin surfaces are: plain, louvered, strip, pin, perforated and wavy. Wavy-fin surfaces are high performance surfaces whose performance characteristics are similar to those of strip and louvered-fin surfaces. The change in flow direction induced by fins causes boundary-layer separation that produces effects similar to those produced by complete fin interruption. In the current work, the effect of flow disturbers mounted on the first six peaks of a twelve-peak (15.28 cm × 0.9525 cm × 30.48 cm) Plexiglas™ wavy channel was investigated. The effect of placing additional flow disturbers mid-way on the downhill side of the first six peaks on bottom channel plate was studied. Using a short duration transient conduction test, local heat transfer coefficients were determined and both the pressure drop and friction factor were measured. Experimental test results indicated that the new test model performed better than the model having flow disturbers mounted on its first six-peaks. Placing six additional flow disturbers downhill of the first six peaks resulted in a lower pressure drop and higher heat transfer rate for Reynolds Numbers of 1500 and 2900 when compared to the results obtained from a similar wavy channel with six flow disturbers. The experimental results agreed with the results obtained using Fluent™, a Computational Fluid Flow and Heat Transfer package.