Використання методу регулярного теплового режиму для визначення коефіцієнта тепловіддачі в молочних продуктах

Abstract

Milk is a complex liquid. Its main components are water, lactose, fat, protein and minerals, but their relative amounts depend on genetics, season, diet and production level, etc. Processing of various dairy products - butter, cheese, condensed milk, yogurt, etc. requires many technological ways. One of the most important requirements of modern dairy production is the ability to control the temperature of products at each stage of the process. Therefore, heating and cooling are very common operations at a dairy plant. Heat exchangers have become a critical component of milk processing, and without them many dairy products would be considered unsafe for consumption due to the growth of harmful microorganisms. Heat exchangers are used in numerous processes, including pasteurization, sterilization, and other needs of the food industry. The work establishes the existence of a regular thermal mode in the system “environment (water in an annular volume) — thin cylindrical metal wall — experimental liquid medium”. Milk and whey were chosen as the experimental liquid medium. Heat exchange under conditions of free convection is studied. It was experimentally established that in the experimental system ”environment (water in an annular volume) — thin cylindrical metal wall — experimental liquid medium” there are signs of a regular thermal mode, that is, the constancy of the rate of cooling (heating) of the experimental liquid medium in a thin cylindrical metal vessels; the constancy of the heat transfer coefficient in the process of a regular thermal mode is practically constant; constancy of the coefficient of nonuniformity of temperature distribution. Using the method of a regular thermal mode, the coefficient of heat transfer to dairy products was determined using the experimental and calculation method. The coefficient of heat transfer to milk during heating is within 640…700 W/(m2·K), to whey during heating — 710…820 W/(m2·K), to milk whey during cooling — 430…500 W/(m2·K).