Використання регулярного теплового режиму для прогнозування інтенсивності теплообміну у відходах птахівництва

Abstract

The system “environment (water in an annular volume) — a thin cylindrical metal wall — the investigated liquid medium” is being studied. Heat exchange during heating and cooling of water-diluted chicken litter under conditions of forced convection is studied. Chicken droppings represent a multiphase medium, as it consists of solid particles based on a liquid medium. The research is carried out on an experimental stand developed at the Department of Thermal Power Engineering of the National Technical University of Ukraine. Experiments are conducted under conditions of forced convection. Average temperatures are defined as arithmetic averages, based on the results of temperature measurement by thermocouples on vertical thermoprobes at a certain point in time. Processing is carried out by the method of stationary heat exchange, examining the entire period of time. After conducting an analysis of the distribution of excess temperature over time Lnϑ = f(τ) during the study of heat exchange of chicken litter under the conditions of its cooling and heating, a linear rate of cooling/heating m = const was determined, which is characteristic of a regular thermal regime during cooling/heating of a solid body (system of solid bodies) and maintaining the stability of the ambient temperature. It was experimentally established that there is a regular thermal regime in the experimental system: the rate of cooling/heating is constant, m = const; the heat transfer coefficient during the regular thermal regime is practically constant. The coefficient of heat transfer from the inner wall of the cylinder to the studied environment was determined by the method of regular thermal regime and the calculation-experimental method. After analyzing and comparing the heat transfer coefficients calculated using the calculation-experimental method and found by the method of regular thermal regime, a discrepancy of 20 % was established. It was established that, the method of a regular thermal regime can be used to determine the intensity of heat exchange in multiphase media.