ABSTRACT
Air impingement heating is an efcient technology because it has high heat and mass transfer rates. During the air impingement process, high-velocity air impinges on the surface of the products, creates a pseudouidized bed of hot air that suspends the products, makes the thermal boundary layers become thinner, and increases the rate of heat and mass transfer (Xiao et al., 2010a). Air impingement technology has several advantages such as high heat transfer coefcient, four times greater than those found in an electric-heated natural convection oven (Li and Walker, 1996); energy saving, up to 12% compared with the traditional baking process (Li et al., 2013); reduced process time, with air impingement oven and the combination of air impingement and microwave oven taking one-half and one-fourth of the baking time, respectively, compared with conventional oven (Li and Walker, 1996), etc.
