Thermal conductivity of refractory fire bricks

Chinafirebrick provides refractory products, magnesia carbon brick， calcium silicate products, castable & mortar, fire brick china, ladle & tundish nozzle, ceramic fiber with high quality for you. Refractory fire bricks rely on convection and steady state heat transfer, in the middle of the high temperature furnace if there are two refractory bricks, and there are two different temperatures there is a temperature difference. There will be heat transfer process we call heat transfer.

Refractory tiles convection heat is due to the movement of the internal particles of the fluid, the heat of the refractory brick from one to another. In the furnace refractory tiles heat transfer often encountered, when the fluid and refractory brick wall contact with the heat to the refractory wall or heat from the wall to the phenomenon of fluid.

Conduction heat transfer, also known as thermal conductivity, thermal conductivity is dependent on the thermal movement of micro-particles and the heat from the refractory high temperature zone to the low temperature area, or from the high temperature refractory brick to contact with the low temperature refractory brick process. In the hot environment, the temperature field of the temperature distribution in the interior of the refractory bricks is changed from time to time to the steady state temperature field.

Heat transfer rate: refers to the unit time through the heat transfer surface heat transfer.Heat flux: refers to the unit time through the unit heat transfer surface heat. Heat flux, also known as heat density.

Steady state heat transfer
The heat transfer process at which the temperature of the points in the heat transfer system varies only with the position and does not change with time. The process of steady state heat transfer is characterized by a constant heat transfer rate through the heat transfer surface.

Non - steady state heat transfer
In the non-steady state heat transfer system, the temperature along the points not only changes with the position, but also changes with time. In general, the heat transfer process of the intermittent production operation is non-steady state heat transfer.
There have many refractory news and refractory products information on web. You can read more refractory products and know more refractory materials information. Because our website has many kinds of refractory news and industry news. what's more ,you can know more kinds of refractory information from our website.
Article Source: Thermal conductivity of refractory bricks
Company name: Henan Xinmi Changxing Refractory Materials Co.,Ltd
Email: sales1@chinafirebrick.com
Website:http://www.chinafirebrick.com/

Come to know the Types of refractory fire bricks

Refractory fire brick manufacturers said that this refractory , high strength, simple construction, wide range of uses, easy to draw, suitable for a variety of industrial furnace masonry, its use and use of different temperatures.
1. Physical and chemical indicators of ordinary refractories clay brick, the size of the allowable deviation and shape products cross-section, should meet the specifications.
Ordinary refractory clay brick for the general furnace refractory masonry. Lining materials, furnace wall, bottom, flue and other operating temperature below 1250 ℃. Combustion chamber parts, allowing the use of more than 1400 ℃.
2. High aluminum brick physical and chemical indicators, product size, allowable deviation, etc., should comply with the provisions of the specification. High alumina bricks are used in general furnace high temperature, wear resistant areas or larger load masonry, burner bricks and special requirements of the masonry. The high temperature zone of the combustion chamber of the dome, allowing the use of temperature 1300 ~ 1650 ℃.
3. Lightweight clay brick physical and chemical indicators, product size allowable deviation and shape products cross-section requirements, should meet the specifications. Lightweight refractory clay brick, as not from the high temperature slag and erosive gas erosion of the furnace lining, according to the different capacity, the use of temperature between 1150 ~ 1400 ℃.
Zhengzhou Changxing furnace refractory material Tips: You may also on the refractory bricks, refractory manufacturers, refractory bricks prices, high alumina refractory bricks, clay refractory bricks, Henan refractory brick factory, Zhengzhou refractory brick factory, Xinmi refractory brick factory .Welcome to view our web to know more kinds of refractory products .

Article source: Types of refractory fire bricks
Company name: Henan Xinmi Changxing Refractory Materials Co.,Ltd
Email: sales1@chinafirebrick.com
Website:http://www.chinafirebrick.com/

Thermal conductivity of refractory bricks

The thermal conductivity of refractory fire bricks is represented by the thermal conductivity that has the ability to transfer heat. Thermal conductivity represents the amount of heat per in unit area, unit time and unit temperature gradient in the energy transfer process.
At 1000 ℃The thermal conductivity of various refractory bricks rate as shown below. The thermal conductivity of different materials is often very different. At normal temperature, the thermal conductivity of various refractory bricks can be from a few percent to several tens (w／(m·℃), which is nearly a thousand times lowst than the highest value. As the temperature rises, although the difference between the thermal conductivity of various refractory bricks tends to decrease, but the difference is still large. Such as 1000 degrees centigrade, the thermal conductivity of lightweight silica is only about 0.35W, recrystallized silicon carbide products is about 17.5W／(m·℃), graphite can be up to 35W / (m·℃).
In addition to temperature, the thermal conductivity of refractory bricks?is closely related to its chemical composition and structure. When refractory bricks?are made of crystal, the properties of crystal have obvious influence on thermal conductivity. As we all know, the thermal conductivity of inorganic nonmetallic materials is generally much lower than that of metal. Because inorganic nonmetallic materials are different from metals with metal bonds, there are very few free electrons. The thermal conductivity caused by free electrons in this material is extremely limited, and the lattice vibration is mainly deviated from the degree of resonance. The greater the degree of deviation from the resonance, the thermal conductivity is smaller. The degree of lattice vibration deviation increases with the difference in the molar mass of the constituent components, so the thermal conductivity of the element is the largest. (So the thermal conductivity of graphite is relatively large).
China refractory bricks have a complex structure of crystals, the thermal radiation of the lattice is greater and the thermal conductivity is smaller, such as MgO, A12O3 and MgAl2O4 Such as MgO, A12O3 and MgAl2O4 are equiaxed, but the structure of MgAl2O4 is complex and the thermal conductivity is low. Non-coherent crystals, in the direction of dense particles along the crystal, thermal conductivity is larger. The quartz along the C axis has a dense accumulation of particles, and its thermal conductivity (13.6W／(m·℃))?is about twice as high as that of the C axis. The layered structure of graphite, the thermal conductivity parallel to the direction of the level of about 4 times in the direction perpendicular to plane direction.
If the crystal is defective, the formation of substitutional solid solution, because the rules of the crystal structure of the destruction caused by thermal scattering phenomenon, resulting in a decrease in thermal conductivity. Other crystal defects such as vacancies, dislocations and so on, also has a similar effect. Due to the thermal scattering of the grain boundary, the thermal conductivity of the polycrystalline material is lower than that of the single crystal. The material of fine grain is lower than that of coarse grain. The refractory raw material contains impurities, the thermal conductivity is lowered due to the scattering effect.

When refractory bricks contain glass phase, due to the amorphous structure of the disorder, the probability of collision between atoms. ?So compared with the crystal, thermal conductivity is low.?When the refractory brick contains pores, because the thermal conductivity of the gas is smaller than the solid, so with the increase in porosity, the thermal conductivity of the material decreases. This is the basic reason for the low thermal conductivity of porous materials. There have many kinds of refractory products in our factory. Such as Taphole Brick, fire bricks for sale, refractory nozzle and other refractory products.
Article source: Thermal conductivity of refractory bricks