Numerical analysis of a heat loss of channel-free heat pipeline in the real application conditions

The results of mathematical modeling of heat regimes of channel-free heat pipeline, as well as numerical analysis of heat loss of channel-free heat pipeline in conditions of freezing ground and the presence of snow cover area were given. The laws of heat transfer in the system and the factors that influence the intensification of heat losses are shown. It was revealed that the normative calculation method of heat loss of channel-free heat pipeline gives overestimated values of heat loss

Heat loss of underground channel heat pipelines with strained thermal insulation layer, taking into account radiative heat transfer in the cavity of the channel

The weakest places of centralized heating systems are the pipelines. Heat pipe network systems, built in the USSR, are characterized by low reliability, high damage possibility and large heat losses. The main reasons for the heat losses growth are moisture, deformation and breakage of the thermal insulation layer.The purpose of this paper is to assess the extent of underground channel pipelines with strained thermal insulation layer heat losses, taking into account radiative heat transfer in the cavity of the channel.During the work the numerical analysis of thermal insulation layer deformation effect and radiation heat transfer in the cavity of the channel influence on thermal conditions and heat losses of underground channel pipelines was achieved. On the basis of these results the perspective of the developed model and numerical analysis techniques for the extent of pipelines with deformed thermal insulation heat losses evaluation was determined

Numerical probability analysis of low-temperature insulation destruction under the condition of periodic duty

The numerical investigation of thermal stresses within low-temperature insulation covering cryogenic pipelines and the numerical probability analysis of low-temperature insulation destruction under the condition of periodic duty were carried out. The minimal longevity values for foamed polyurethane and mineral cotton were established. The results of longevity analysis for foamed polyurethane and mineral cotton under the condition of environment temperature variation were obtained

Heat loss of heat pipelines in moisture conditions of thermal insulation

Results of numerical simulation of heat and mass transfer in a wet fibroporous material in conditions of evaporation and steam diffusion were obtained. Values of heat and mass fluxes were established. The contribution of evaporation effect to total heat flux and need to consider volume fractions of water and steam into the structure of fibroporous material in calculation of effective thermal conductivity were shown. Nonstationarity of heat and mass transfer in conditions of considered problem can be ignored

Numerical analysis of the effect of freezing ground in the laying zone pads on heat loss of channelless pipelines laid out without canals

The results of mathematical modeling of heating mains laid out without canals, as well as numerical analysis of their heat losses in the presence of ground freezing in the area of installation are presented. The laws of heat transfer in the system and the factors influencing the intensification of heat losses are established. It was revealed that the regulatory calculation method of pipelines’ heat losses gives overestimated values. It was found that the heat losses of pipelines subject to ground freezing in the laying zone rise by 1.65–5.04%. The deviation between the heat losses of pipelines is about 21–27%, taking into account the freezing ground in the laying zone and heat losses, calculated according to standard methods. That indicates the need to adjust the regulatory procedure. These results suggest promising application of the developed approach to the analysis of thermal conditions and heat loss of heating mains laid out without canals in conditions of freezing ground in the laying zone and the possibility of its use in the creation of energy efficient heat transfer system

Numerical analysis of an engineering structure effect on a heat loss of channel-free heat pipeline

The results of mathematical modeling of thermal modes of channel-free heating network laid in the areas of influence of engineering structures, as well as numerical analysis of the heat loss of the objects submitted. The regularities of heat transfer in the system and the factors that influence the intensification of heat losses are revealed. Revealed that thermal losses heating pipes laid in the channel-free zones of influence engineering structures decreases in the range from 1.53 to 10.79%, depending on the temperature inside the engineering structures and geometric characteristics of the system. It is shown that the standard method of calculation of heat loss channel-free heating pipes gives overestimated values of heat loss

Numerical analysis of a heat loss of channel-free heat pipeline in the real application conditions

The results of mathematical modeling of heat regimes of channel-free heat pipeline, as well as numerical analysis of heat loss of channel-free heat pipeline in conditions of freezing ground and the presence of snow cover area were given. The laws of heat transfer in the system and the factors that influence the intensification of heat losses are shown. It was revealed that the normative calculation method of heat loss of channel-free heat pipeline gives overestimated values of heat loss

Application of a Convective-Conductive Heat Transfer Model in the Heat Loss Analysis of a Heat Pipeline Under Flooding Conditions

This paper describes the numerical modeling of a convective-conductive heat transfer the area placing of a heat pipeline under flooding conditions. We have established that the heat loss of a heat pipeline under flooding conditions increases in the range from 1.5 to 64.3%, depending on the volume fraction of water in the insulation structure

Thermal Mode of Tanks for Storage Fuel of Thermal Power Plants and Boiler with the Influence of Engineering Facilities in the Area of their Placement

This paper describes the numerical modeling of heat transfer in the area placing of the tank for storage fuel of thermal power plant and boiler with the influence of engineering construction. We have established that the presence of engineering structures in the area of placing of the tank for storage fuel of thermal power plant and boiler have little effect on the change of heat loss