Analysis of thermal processes during the preparation of deep-fried foods
Students Name: Hainiuk Petro Mykolaiovych
Qualification Level: magister
Speciality: Food and Processing Industries Equipment
Institute: Institute of Mechanical Engineering and Transport
Mode of Study: full
Academic Year: 2020-2021 н.р.
Language of Defence: ukrainian
Abstract: Gajnyuk P.M., Velyka O.T. (supervisor). Analysis of thermal processes during the preparation of deep-fried foods. Master’s thesis. – Lviv Polytechnic National University, Lviv, 2020. Extended abstract. Object of research: deep-fried food cooking installations. Subject of research: thermal processes that occur during the preparation of deep-fried foods by frying. The purpose of the study: to reduce the consumption of thermal energy by the installation of food preparation in a deep fryer while maintaining its productivity. To analyze the thermal processes in the preparation of food in a deep fryer, first determine the amount of deep fryer that will be used for frying, respectively, will be heated and maintained at a certain temperature. It is determined by the maximum amount of product that will be fried (its weight and volume), and it, in turn, depends on the required maximum performance of the installation. Next, using the heat balance equation, determine the required amount of heat required for the installation of deep-fried food. During operation of the investigated installation it is possible to allocate three modes of its work: the mode №1 of heating of a deep fryer and a bath after switching on of installation from ambient temperature to frying temperature; mode №2 - operating mode of frying, in which the products are manufactured. This mode is accompanied by maintaining a constant required process temperature of frying, which is constantly laid raw dough pieces (they must be heated). Also, heat loss occurs due to topping up the deep fryer in the bath (it also needs to be heated), due to the absorption of heated fryer during frying. Also, heat losses during the operation of the installation occur through the upper cover of the bath and its insufficient thermal insulation through the side walls and bottom, air heating, etc .; mode №3 cooling of the installation - its heated parts after disconnecting the installation from the network after its completion. In this case, it will not consume external energy, but will give off heat to the environment until the temperature is completely equal to it. The next step was to determine the amount of heat lost during operation. Heat loss during the operation of the device for cooking food in a deep fryer will be in any case, no matter what the thermal insulation of the bath. They are used to heat the most structural elements of the installation as well as to heat the environment (air in the room where it operates). These heat losses occur in all the above modes of operation of the installation, and in modes №1 and №2 (exit to operating mode and the work itself) - these losses are parasitic, and in mode режи3, when the installation is cooled - useful. The magnitude of these losses can be reduced by increasing the level of thermal insulation of the installation, but in the thermal calculation and study they must be taken into account. Based on the laws of thermodynamics, the loss of thermal energy by the installation for cooking food in a deep fryer will be in two ways: convection - due to intermolecular interaction between air molecules in the area of operation of the installation; infrared radiation - heat transfer by waves. The heat loss unit of the deep-fried food will also be through a ventilated exhaust system, which is located above the deep-fried bath and draws in air with high-humidity fryer vapors. However, these losses should be taken into account when the installation goes into operation, when the fryer is fully heated. The amount of heat consumed to heat the installation itself was also determined. The greatest consumption of thermal energy by the installation of cooking food in a deep fryer occurs when it enters the operating mode of frying. Energy is spent on heating the fryer, the installation itself and the environment. On the basis of the selected and analyzed method of thermal calculation of the installation, it is possible to make a calculation for other productivity of the installation and for frying another type of product. Also, a number of graphical dependences for determining the appropriate type of heat depending on the parameters of the installation for different modes of its operation. The design calculation of the device of installation of cooking of products in deep fryer is carried out in work. As part of this, the calculation of the required power of the drive of the installation, calculated gear ratios, torques and power of the elements of the drive of the installation, the calculation of the belt drive of the drive of the installation. Key words: installation, deep fryer, food product, frying, heat process, heat loss, dough preparation.