## Evaluation of the Radiation Coefficient Effect in Total Heat Transfer between Network Pipelines and Water Pipes in the Joint Installation

**Stepanov A.V., Egorova G.N.**

**This paper considers a mathematical model of joint laying of water pipeline networks and district heat networks. The purpose of the work is to study the effect of radiation on the process of complex heat exchange taking place in the housing insulation between structural elements. The results of mathematical simulation of the heat loss taking into account the radiant component are given. When calculating the heat flows which are lost in the pipeline through thermal insulation at transporting the coolant, the heat transfer process is usually considered by means of conduction and convection. The radiant component is neglected in most cases. The influence of heat transfer by radiation and convection is particularly noticeable using thermal insulation products with large pores and air gaps. A ground configuration of a pipe line and water pipe line laid in a joint thermal insulation made of mineral wool is considered. When laying joint pipelines, complex radiative heat transfer occurs. It consists, for each one of these pipelines, of radiation reflected from the other pipeline and self-radiation. A non-stationary temperature field of the structure, consisting of two parallel stacked pipes with different diameters lying in a joint insulating structure made of mineral wool, is calculated. The construction elements exchange heat with each other and the environment by convection and radiation.**

Key words: mathematical model, total heat transfer, heat losses, radiation coefficient, non-steady temperature field, total heat flux.

**Science and Education, 2017, No.4, pp. 93-98.**