Heat transfer enhancement in vertical channel for two phase flow by using compound turbulater

الملخص EN

The mixture of air-water (gas-water) flow has many applications in chemical and mechanical industries and heating systems (heat exchangers and manifolds), fields of energy, petroleum, refrigeration, and air conditioning.

The characteristics of the mixture (water, air) have been investigated experimentally in a rectangular channel placed vertically by using internal heated plate (compound turbulater ribs and groove) with different volume flow rates of water and air, and constant heat flux.

The dimensions of the rectangular channel are (5 × 3 × 70 cm).

The aim of these experiments is to display the two-phase flow phenomenon with heated plate (three compound turbulater) for different water and air discharges.

Four different values of water flow rate (3, 6, 9, and 12 l/min), three different values of air flow rate (8.33, 16.67, and 25 l/m), and three different values of heat power (109.65, 150, and 235 watts) have been used.

The temperature of the mixture has been measured at several locations along the channel, and the behavior for the mixture inside the channel has been visualized by using video camera.

The results showed that when water and air flow rate increases, flow becomes turbulent, vortices develops around the heated plate, the exit temperature decreases and local heat transfer coefficient increases.

The compound turbulater with relative groove position (g/p)=0.55 had a higher rate of heat transfer ,where the percentage difference from other model (g/p = 0.73 and 0.37) were 4% and 6% , respectively due to the fact that the flow mixing and sweeping surface in these types of compound turbulater are more than others type.