Fire danger of interaction processes between local heat sources and condensed substances

Biomass as fuel is used for many years. At present it is important to effectively use energy sources because price of energy is more and more expensive. This is the main reason for building of modern low-energy houses. The projected thermal performance of these buildings rarely exceeds 4-6 kW. During most days of heating season these buildings need only 2-4 kW of heat but almost all produced heat sources have nominal thermal power higher than 10-15 kW. Because of this the thermal power of majority heat sources is oversized and using of them could be complicated. One of the solutions of this problem should be heat storage in accumulation vessels. The paper deals about using of local heat source with warm-water heat exchanger for combustion of wood biomass. There were tested thermal and emissions parameters of wood stoves. There was measured thermal power to air and to the accumulation vessels, production of carbon monoxide (CO), production of nitrogen oxides (NOx) and production of particulate matters (PM). The results shows that local heat sources with warm-water heat exchanger for combustion of wood biomass could be used for heating of new low-energy buildings.

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Mathematical Modeling of Heat and Mass Transfer Processes with Chemical Reaction at Polymeric Material Ignition by Several Small-Size Hot Particles

Mathematical Problems in Engineering ◽

10.1155/2015/614143 ◽

2015 ◽

Vol 2015 ◽

pp. 1-8 ◽

Cited By ~ 2

Author(s):

Dmitrii O. Glushkov ◽

Pavel A. Strizhak

Keyword(s):

Mass Transfer ◽

Heat And Mass Transfer ◽

Polymeric Material ◽

Local Heat ◽

Material Surface ◽

Heat Sources ◽

Hot Particles ◽

Transfer Processes ◽

Mass Transfer Processes ◽

Air System

Numerical research of interconnected heat and mass transfer processes in the “two hot particles—polymeric material—air” system was executed. The joint effect of several local heat sources on the main integrated characteristic of ignition process (ignition delay time) was established. Two ignition models characterized by the relative positioning of hot particles on a polymeric material surface were revealed. Besides, there were established characteristics of local heat sources and the distance between them (700 K<Tp<1150 K andL>1.5orTp>1150 K and0.25<L<1.5)when regularities of heat and mass transfer processes in the “two hot particles—polymeric material—air” system are similar to regularities of heat and mass transfer processes in the “single hot particle—polymeric material—air” system.

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Effects of Protrusions on Conjugate Heat Transfer in a Microtube or Microchannel

2010 14th International Heat Transfer Conference, Volume 6 ◽

10.1115/ihtc14-23319 ◽

2010 ◽

Author(s):

Muhammad M. Rahman ◽

Phaninder Injeti

Keyword(s):

Heat Transfer ◽

Reynolds Number ◽

Conjugate Heat Transfer ◽

Local Heat Transfer ◽

Local Heat ◽

Heat Sources ◽

Two Dimensional ◽

Discrete Heat Sources ◽

Global Performance ◽

Tube Geometry

Effects of protrusions on heat transfer in a microtube and in a two-dimensional microchannel of finite wall thickness were investigated for various shapes and sizes of the protrusion. Calculations were done for incompressible flow of a Newtonian fluid with developing momentum and thermal boundary layers under uniform and discrete heating conditions. It was found that the local Nusselt number near the protrusions changes significantly with the variations of Reynolds number, height, width, and distance between protrusions, and the distribution of discrete heat sources. The results presented in the paper demonstrate that protrusions can be used advantageously for the enhancement of local heat transfer whereas the global performance may be enhanced or diminished based on the tube geometry.

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Heat Conduction in Composites: Homogenization and Macroscopic Behavior

Applied Mechanics Reviews ◽

10.1115/1.3101714 ◽

1997 ◽

Vol 50 (6) ◽

pp. 327-356 ◽

Cited By ~ 34

Author(s):

Piotr Furman˜ski

Keyword(s):

Heat Conduction ◽

Effective Properties ◽

Constitutive Relations ◽

Local Heat ◽

Temperature Fields ◽

Heat Sources ◽

Ensemble Averaging ◽

Macroscopic Behavior ◽

Classical Behavior ◽

Homogeneous Media

The review article discusses methods of macroscopic averaging of heat conduction in composite materials that lead to models of homogenized, macroscopic behavior of these media. It is shown that essentially two continuum models are in use: 1) the effective medium and 2) the mixture. The ensemble averaging technique allows one to derive the constitutive relations for both models assuming Fourier-like conduction on the microstructure level of a composite. These constitutive relations contain effective, macroscopic properties of the composite material which can be forecast when properties of individual constituents, the form of thermal interaction at constituent interfaces, amount of each material and its distribution are known. For weakly varying mean temperature fields, thermal behavior of the composite is essentially the same as homogeneous media but, for stronger variation, a non-classical behavior is observed. This non-classical behavior can be associated either with space nonlocality and memory phenomena or with wall effects and, in some cases, with influence of local heat sources on the effective properties. Most of these effects are not well known and need further detailed studies. The article includes 158 references.

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Generation of dislocation loops in silicon near local heat sources

Inorganic Materials ◽

10.1134/s002016850606001x ◽

2006 ◽

Vol 42 (6) ◽

pp. 581-585 ◽

Cited By ~ 1

Author(s):

A. A. Skvortsov ◽

A. M. Orlov ◽

V. V. Rybin

Keyword(s):

Local Heat ◽

Heat Sources ◽

Dislocation Loops

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