Experimental Assessment of Capital-Cost Reduction in a Helical Coiled-Tube Heat Exchanger Using Shell-Side AirBubble Injection

Abstract

Integrating air bubbles into the liquid phase of thermal exchangers serves as an efficient active strategy for improving convective heat transfer. This research examines the possibility of decreasing capital costs by incorporating tiny bubbles onto a Vertical - shell's shell side -and-helical-coiled-cylindrical thermal exchanger through a porous sparger. The thermal efficiency was assessed by altering the water flow rates on the shell side, the air injection flow rates, and the fluctuations in intake temperature. The comprehensive thermal transfer coefficient was determined by the experimental energy balancing and the logarithmic average temp discrepancy, whereas the thermal transfer area scaling, according to the six tenths rule, was employed to forecast the cost trajectory. Bubbling raised the total coefficient appreciably, with a maximum enhancement of approximately 119%. At a fixed heat duty, this implies a thermal transfer-area reduction of approximately 54.3% and, under the six-tenths rule, a predicted capital-cost reduction of approximately 37.5%. Shell-side bubbling therefore appears able to improve the economics of compact coiled-tube exchangers. The conclusion is conditional, however: compressor cost, air-injection power, pumping power, maintenance, and long-term reliability were left out of the present cost estimate.