Abstract
In air-blast freezer, there are differences in food freezing process at different locations due to the non-uniform airflow distribution in freezing chamber. In this paper, a decoupling method was used to simulate freezing process of food products at different locations. Firstly, the internal airflow distribution model of the freezing chamber was established to simulate the airflow field in freezing chamber under different velocities of air supply. The mainstream air flow rate around each food product was then calculated as the ambient air velocity at which the food freezes. Then, a validated lumped parameter model was used to simulate the freezing process of individual food product, and the effects of freezing conditions on freezing process at different locations were studied. The results showed that there were large differences in the freezing conditions of foods at different locations in freezing chamber, which were mainly reflected by the difference in ambient air velocity. Compared to air velocity, air temperature was distributed rather uniformly in freezing chamber. With the increase of supply air velocity of air coolers, the ambient air velocity around food products in freezing chamber increased almost linearly.
Highlights
In freezing chamber of cold storage, the forced convection is usually used to freeze the food
Where, V is the volume of the food, m3; H is the volumetric devaluation of the food, J/m3; k1 is the thermal conductivity of the food before freezing, W/(mK); ks is the thermal conductivity after food freezing, W/(mK); Tm is the food center temperature, °C; X is the characteristic length of the food, m; E is the equivalent heat transfer dimension; L is the phase change latent heat of food, J/m3; The calculation method of food devaluation and parameters such as parameters n, N, β1 in the equation can be found in the literature[12]
The non-uniform distribution of airflow field usually results in different freezing conditions of food products at different locations, which leads to the difference in freezing process of food products
Summary
In freezing chamber of cold storage, the forced convection is usually used to freeze the food. For specific food parameters such as food type, shape, size and packaging, the freezing process mainly depends on the airflow distribution around food product, including air temperature, velocity and turbulence. The internal airflow field distribution in the freezing room was simulated to calculate the air parameters around each food product as the freezing condition. Simulating the external airflow field and the heat and mass transfer inside food product simultaneously can be time-consuming. The premise of a stepwise approach in this paper is that the convective heat transfer coefficient between food and air remains constant during the freezing process. The forced convection heat transfer coefficient mainly depends on the air parameters around the food, including air velocity and turbulence intensity. In this research the natural convection was not considered as the air velocity around food generally exceeds 0.5m/s in air-blast freezer
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
