Experimental Study of Convective Heat Transfer in Miniature Double Tube Hair-Pin Heat Exchanger

In this paper, we present experimental investigation of convective heat transfer characteristic in the inner tube fluid of miniature concentric double tube Hair-pin heat exchanger with constant heat flux. This work is carried out for distilled water and a mixture of distilled water and ethylene glycol (10%, 20% and 25% by volume) as heat transfer cold fluid flowing in inner tube to carry away heat from the annulus hot fluid. The obtained Friction factor and heat transfer coefficient are compared with the existing conventional correlations. The present experimental results show that mixing of ethylene glycol in distilled water enhances the thermal performance of the miniature heat exchanger considerably for both laminar and turbulent flow in counter flow arrangements. From the experimental results obtained it’s also found that thermal performance is better in laminar region than turbulent region. KeywordsConvective heat transfer coefficient, Laminar flow, Nusselt number, Turbulent flow.