Effect of swirl flow on whey protein fouling and cleaning in a straight duct

Whey protein fouling is a complex phenomenon involving several mechanisms. Product, surface properties and process parameters interact simultaneously. This experimental work focuses on the effect of a swirl flow on whey protein fouling and cleaning in a straight tube, independently of any other factors. In a holding section after a heating zone composed of a plate heat exchanger, the dry deposit mass obtained from a straight tube was compared with that obtained in the presence of a swirl flow. For varying conditions, namely two protein concentrations, two processing temperatures and two fouling durations, the dry deposit mass increases despite the wall shear stress increase induced by the swirl device. Nevertheless, the cleaning time was found to be significantly shorter in presence of swirl flow in laminar and turbulent conditions. These results reveal that cleaning efficiency can be improved by such a swirl insert, which is seldom used in the food process industry.