Convection Heat Transfer In Furnace

The configuration of furnaces is such that two radi ant zones have one common convection section for heat recovery.

Convection heat transfer in furnace.

Furnaces employing combustion produce a hot gas which transfers heat to the material by radiation and convection. The area is filled with tubes or pipes which carry process steam and which absorb heat via convection heat transfer from the hot gases passing through the area on their way out of the stack. Heat transfer takes place by convection here and the tubes are finned to increase heat transfer. The first three tube rows in the bottom of the convection section and at the top of the radiant section is an area of bare tubes without fins and are known as the shield section shock tubes so named because they are still exposed to plenty of radiation from the firebox and they also.

Although often discussed as a distinct method of heat transfer convective heat transfer involves the combined processes of unknown conduction and advection. Theory and calculation of heat transfer in furnaces covers the heat transfer process in furnaces how it is related to energy exchange the characteristics of efficiency and the cleaning of combustion providing readers with a comprehensive understanding of the simultaneous physical and chemical processes that occur in boiler combustion flow heat transfer and mass transfer. The convection section is located above the radiant section where it is cooler to recover additional heat. The three sources of heat energy are i combustion of fuels ii electric energy and iii chemical energy available through the exothermic reactions.

Convection is usually the dominant form of heat transfer in liquids and gases. Alternatively a regenerative heat exchangermay be used to transfer heat from the combustion gases. Convective heat transfer often referred to simply as convection is the transfer of heat from one place to another by the movement of fluids. The rest of the radiation is partly absorbed by glass interior absorptance depending on glass thickness which slightly decreases the thickness wise temperature gradient and thermal shock in glass at initial stages of the heating.

Solids are heated by direct contact but fluids are usually heated indirectly being carried inside pipes within the furnace. Convection contact heat transfer as well as about 46 of the radiation in a tempering furnace affect glass surfaces from which heat is conducted deeper into the glass. Convection heating uses gas in most cases nitrogen or argon at a higher temperature than the furnace chamber as well as a fan to circulate heat to all parts in the load. Heat transfer is only one process in the furnace for which an exact solution cannot be obtained unless four groups of equations corresponding to the four processes are solved simultaneously.

The gas path for the turbotreater vacuum furnace with the added option of convection heating. The convection section forms an obstacle to the combustion gas flow and can greatly affect furnace draft in the radiant section of the furnace.