The transportation time, temperature, and vehicle hygiene status of fresh and cold meat directly affect its quality and shelf life. Using refrigerated trucks as carriers, monitor their temperature, relative humidity (RH), and wind speed over transportation time; Study the disinfection effect of different dosages of sodium hypochlorite on carriages; Using a constant temperature of 4 ℃ as a control, cold fresh meat was transported under temperature conditions of 1 ℃ increase, 2 ℃ increase, 1 ℃ turbulence, and 2 ℃ turbulence, and the effect of temperature change on its quality was studied; Finally, the transportation conditions of cold fresh meat were optimized through orthogonal experiments. Effect note: The RH diffusion inside the refrigerated car is average, with the fastest cooling, the least temperature turbulence, and the highest wind speed below the refrigerator, followed by both sides of the car; 300 mg/kg sodium hypochlorite has a better disinfection effect; There was no significant difference in pH value, total volatile base nitrogen content, juice loss rate, and total bacterial count between the meat sample and the control group under temperature 1 ℃ turbulence conditions (P>0.05); Optimize two transportation conditions, namely accepting 300 mg/kg sodium hypochlorite to disinfect the carriage, transporting for 6 hours, and ensuring the quality of fresh cold meat under constant 4 ℃ or temperature fluctuations of 1 ℃.
In the process of transporting goods in refrigerated trucks, the thickness of the cold insulation layer and the selection of materials directly affect the cold insulation effect of the carriage. For differences in other thicknesses, materials, vehicle speed, cold insulation temperature, and external temperature, a physical model can be established. Through theoretical calculation and simulation, the influence of various parameters on the cold insulation effect can be analyzed, providing a certain basis for the selection of various parameters of the
Refrigerated Truck. As the thickness of the carriage wall is much smaller than its length and width, it can be simplified as an infinite flat wall heat transfer situation, and only the one-dimensional heat transfer that deviates along the thickness of the carriage wall can be analyzed. The simplified outer plate, thermal insulation layer, and inner plate of the refrigerated truck are shown in Figure 4. For the convenience of the calculation of the carriage, the following assumptions are made: ① The carriage sealing plate is calculated as follows: Superior, without signs of air leakage; ② When the temperature of the carriage reaches a steady state, the temperature in all parts of the carriage is diffusely averaged, and the temperature is equal everywhere; ③ Neglecting the significant changes in solar radiation in different regions and seasons
The structure of the refrigerated car compartment was analyzed, and its key parameters were analyzed. The main conclusions were as follows: ① A three-layer structural compartment wall was designed to reduce the weight of the compartment while enhancing the cold insulation effect; ② The designed cold air guide device can quickly and evenly diffuse the temperature of the carriage, achieving good refrigeration effect; ③ A heat transfer model for the carriage was established, and through analysis, it was found that the thickness of the insulation layer, the difference between the refrigeration temperature and the air temperature have a significant impact on the heat leakage rate of the carriage. As the vehicle speed increases, the heat leakage rate of the carriage increases, but it is not significant
