Transient Heat Transfer By Intermittent Shake Of Cans [transferência De Calor Transiente Na Agitação Linear Intermitente De Latas]

摘要

The transient heat transfer during the intermittent and linear shaking of tin plate cans containing simulating food was studied in order to apply this technology in the pasteurization and sterilization processes, achieving energy economy and higher food quality. Transient heat transfer was carried out in four different simulating media: water, Neutral oil 150 and 500 and Bright stock oil. Five treatment combinations were prepared: simulating media (4 levels), head space (3 levels), agitation frequency (4 levels), length of agitation (2 levels) and can positions (4 levels). Heating and cooling tests were carried out respectively in a boiling water tank at 98 °C and in a cool water tank at 17-20 °C. Heat transfer parameters (fh, jh, fc and jc) for each test were calculated and the results expressed using dimensionless numbers relations as Nusselt, Prandtl and Reynolds and trigonometric functions. Two equations were defined: Nu = ReA -0.199.Pr -0.288.sen(xa/AM) 0.406.cos(xf/FA)-1.039.cos((xf/FA).(EL/H).π) -4.556 Heating Nu = 0.1295.ReA-0.047.Pr -0.193.sen(xa/AM)0.114.cos(xf/FA)-0.641. cos((xf/FA).(EL/H).π)-2.476 Cooling The intermittent linear shaking increases significantly the heat transfer rates in the heating and in the cooling process phases. This system could be adapted to static pasteurizer or sterilizer with simple internal structure modifications.