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MODELLING OF HEATING OF THE INGOT
IN REGENERATIVE HEATING WELLS

With application of mathematical modelling it is considered Heating of ingots in regenerative heating wells. Alternate submission Fuel through regenerators leads to asymmetrical heating of ingots. Reduction of time between switching valves with identical rate of growth On each interval process allows to intensify temperatures of the furnace Heating of ingots and to reduce fluctuation of temperatures.

Introduction

the Oven facilities of factories of ferrous metallurgy of Ukraine Consumes a plenty of fuel. Till now the core Source of fuel was natural gas. However deficiency of natural gas and Sharply increased cost for 1000 m forces Consumers sharply to reduce use of natural gas and to find others Sources of heat.

In this connection the role regenerative has increased Heating wells, which owing to heating of air and gas up to high Temperatures, can work on low-calorie fuel   as on domain Gas, and on mixes.

In connection with the arisen problem of economy of fuel The decision problems by various criteria of an optimality is necessary. One of such criteria is optimization on a minimum of the charge of fuel.

Work of regenerative heating wells is connected With cyclic submission of fuel. Such submission of fuel leads to that The ingots costing at an ardent window, are heated non-uniformly.

the Analysis of the received results

  °Ñ with the sizes 0,715 ´ 0,65 ´ 2,33   m. At calculation it is accepted, that The identical sizes have the top and bottom basis of an ingot.

the Near side of an ingot Cooperates with the products of combustion leaving an ardent window; distant The side is in a zone of weak circulation, sides are equally washed by products Combustions, therefore the temperature of environment on these sides changes in regular intervals.

1 curves Resulted in figure Correspond to two cases of heating with various time switch valves. The first case ( - ) switch valves occurs through = 780 ñ, in the second Case ( ---) switch valves occurs through = 600 ñ. Both in one and in other case change of temperature of environment through identical number ïåðåêèäêè valves equally. It leads to that temperature of environment at = 600 ñ grows in time more quickly, than At switch = 780 ñ. Than It is less time between switch, that the temperature more quickly grows.

Apparently from figure 1, fluctuation of temperature During the initial moment of time it is not essential a surface, it practically does not go down, And remains to a constant. But since time, approximately, = 4500 ñ temperature Products of combustion from a cell strongly decreases. At smaller time between ïåðåêèäêàìè valves fluctuation of temperature of a surface smaller, than at greater Time between switch. It is connected by that duration of interaction The maximal and minimal value of temperature of environment from a surface of a body It is less and the temperature of a surface will raise or go down on smaller Size.

the Quantity switch will increase at smaller time Between switch valves. At the same growth rate temperature of environment for Certain time will grow up to greater value, and the ingot will get warm up to more Heat.
So, during heating = 7800  (figure 3) At = 600  (---) temperature On a surface has reached value   °Ñ, and in To the middle   °Ñ. At time switch =   780   with ( - ) temperature on a surface   °Ñ, and in To the middle   °Ñ.

 

a Fig. 2 . Change of temperature On section of a body for the various moments of time

 

At the same number ïåðåêèäîê valves an ingot with Smaller time between switch valves will heat smaller time, than Ingot with greater time between switch.

=   600   with Time of heating has made =   4200   with Temperature curve ( ) it is located below, than At =   780   with and general time of heating =   5450   with. In the first case the temperature of a surface is equaled   °Ñ, temperature The middle   °Ñ, and in the second Case   °Ñ,   °Ñ.

If to compare heating ingots on number switch valves, That at greater time between switch ingots are heated longer and temperature on To section will be above, than at ingots at smaller time between switch Valves.

Distributions of temperature on section of a body with a difference in time. During Time from =   9600   with up to =   10200   about products of combustion adjoin With a forward side 1 (figure 2) it is direct at an output from an ardent window. Opposite The side 3 is shaded by an ingot and temperature of environment there less. Distribution Temperatures on section of an ingot it is presented to a curve figure 2 . In a point 1 temperature is equaled   °Ñ, and in a point 10 it is equaled   °Ñ. During the moment of time =   10200   about products of combustion have changed Direction of movement on the return and in current of time from =   10200   with up to =   10800  c the side 3 is heated more intensively, than Side 1. Distribution of temperatures is presented to a curve ( -) figure 3. Temperature on the verge of 1 has gone down and became equal   °Ñ, and on the verge of 3 has raised and It is equaled   °Ñ. In all other points on section temperature Has raised: in a point 2 was equal   °Ñ became equal   °Ñ, in a point 9 it was equaled   °Ñ also has raised up to temperature   °Ñ.

 

Conclusions

Modelling heating of ingots Is executed in Regenerative heating wells in view of non-uniformity temperature Fields in a cell, the fuel caused by cyclic submission, in one, in other Direction.

Dynamics of heating of ingots Is resulted at various Duration between switch valves. Change of temperature of environment at smaller Duration of a cycle with the same intensity, as well as at greater duration Cycle, allows to intensify process of heating not only on a surface Ingot but also to increase speed of rise of temperature of its center.

At identical quantity switch valves greater Time of heating corresponds to greater time between switch valves.