|
|
Specifications in the heat calculation of electrothermal devices
Mikmek, Vladislav ; Foral, Štěpán (referee) ; Lázničková, Ilona (advisor)
This bachelor's thesis deals with the heat calculation of a resistance crucible furnace with emphasis on the influence of selected specifications. The whole process of the heat calculation is described. The calculation used in this thesis requires inputs as the kind of material of the batch or it's weight, the dimensions of the crucible and of the heating elements and others. The output of the calculation is the heat necessary to melt the batch, power needed by the crucible, the dimensions of the resistance spiral, permitted surface load of the spiral and the number of supports in the furnace to hold the heating elements. Parts of the canculation where there is possible to choose different methods to acquire needed values are also mentioned. The last chapter shows on a particular example of crucible furnace the influence of selected specifications on quantities dependent on these specifications. In selected parts of the calculation, that can be done by at least two diffent methods, is shown the influence of the choice on the partial result. In the case of a bigger differences of the results is shown even the influence on the subsequent parts of the calculation and final results. The contribution of the thesis is a summarization of the influences of the selected specifications on the results of the heat calculation. It also shows that some selected specifications have minor and other major influence on the calculation.
|
|
|
Indirect resistance heating
Haluza, Zdeněk ; Foral, Štěpán (referee) ; Lázničková, Ilona (advisor)
The importance of electrical heating technology on a global scale is significant. Resistive heating is one of the many methods that can be used in electrical heating appliances. In direct resistive heating electric current flows directly through the charge. During indirect resistance heating electric current flows through the heating element, where the Joule losses (resistance losses) are arising and from them the charge is heated. In the first five chapters of the bachelor thesis are discussed various methods of heat transfer. The sixth chapter contains basic information about direct resistance heating. In the following chapters I have analyzed only indirect resistance heating. In the seventh and eighth chapters are listed and described parts of the electrical resistance furnace. In the ninth chapter is a general calculation of crucible furnace for melting aluminum followed by real calculation for crucible furnace according to the specified parameters.
|
|
|
Optimalization of indirect resistance heating
Havránek, Miroslav ; Bok, Jaromír (referee) ; Lázničková, Ilona (advisor)
The indirect resistance heating is one of many ways of heating a melting charge. It is used in metallurgy, mostly for melting of soft metals. Its principle is a direct resistance heating in correspondence with the Joule´s law. The principle of indirect resistance heating is in generating of thermal energy in heating element and heat transferring this heat into the melting charge. The theoretical part of this Bachelor Work (the first three chapters) is focused to thermal energy generation and possibility of thermal transmittance. The fourth chapter is devoted to possibility of utilizing of the indirect heating in praxis. The simplest general design and calculation of a pot-type furnace for aluminium melting is done in the fifth chapter. There is a part in this chapter, which deals with the effectivity of the designed pot-type furnace and possibility of heating optimalization in case when indirect heating system is used. The input and calculated parameters of our designed furnace are summed up in the conclusion. There is also comparison of the designed furnace and a furnace readily available on the Czech market and stress on importance of optimalization of heating at indirect heating systems.
|
|
|
Thermal calculation in design of resistance and induction devices
Krčál, Vít ; Foral, Štěpán (referee) ; Lázničková, Ilona (advisor)
This bachelor’s thesis focuses on thermal calculation of electric heating device and related theory. Selected topics in electric heating technology are explained, followed by the calculation in design of a crucible furnace and its automation using a computer program. The theoretical part first deals with the heat transfer mechanisms and their mathematical description. Further on, the thesis describes how heat is created in resistance and induction heating devices and mentions applications of these types of heating. The main part of the thesis focuses on the thermal calculation of the resistance crucible furnace for aluminium melting. The calculation relates to a cylinder-shaped model of the furnace with determined structure and deals mostly with heat loss, electric power input, thermal efficiency and design of heating elements. The calculation is achieved only in general and it is subsequently automated in Microsoft Office Excel® application. The computer program, which is also a part of the thesis, allows user to change input parameters and see how it affects results of the calculation. In the last chapter, an example of calculation for specific numeric data is presented. The main goal of the thesis is to automate the calculation. That can save some time while calculating and designing a crucible furnace.
|
|
|
Specifications in the heat calculation of electrothermal devices
Mikmek, Vladislav ; Foral, Štěpán (referee) ; Lázničková, Ilona (advisor)
This bachelor's thesis deals with the heat calculation of a resistance crucible furnace with emphasis on the influence of selected specifications. The whole process of the heat calculation is described. The calculation used in this thesis requires inputs as the kind of material of the batch or it's weight, the dimensions of the crucible and of the heating elements and others. The output of the calculation is the heat necessary to melt the batch, power needed by the crucible, the dimensions of the resistance spiral, permitted surface load of the spiral and the number of supports in the furnace to hold the heating elements. Parts of the canculation where there is possible to choose different methods to acquire needed values are also mentioned. The last chapter shows on a particular example of crucible furnace the influence of selected specifications on quantities dependent on these specifications. In selected parts of the calculation, that can be done by at least two diffent methods, is shown the influence of the choice on the partial result. In the case of a bigger differences of the results is shown even the influence on the subsequent parts of the calculation and final results. The contribution of the thesis is a summarization of the influences of the selected specifications on the results of the heat calculation. It also shows that some selected specifications have minor and other major influence on the calculation.
|
|
|
Indirect resistance heating
Haluza, Zdeněk ; Foral, Štěpán (referee) ; Lázničková, Ilona (advisor)
The importance of electrical heating technology on a global scale is significant. Resistive heating is one of the many methods that can be used in electrical heating appliances. In direct resistive heating electric current flows directly through the charge. During indirect resistance heating electric current flows through the heating element, where the Joule losses (resistance losses) are arising and from them the charge is heated. In the first five chapters of the bachelor thesis are discussed various methods of heat transfer. The sixth chapter contains basic information about direct resistance heating. In the following chapters I have analyzed only indirect resistance heating. In the seventh and eighth chapters are listed and described parts of the electrical resistance furnace. In the ninth chapter is a general calculation of crucible furnace for melting aluminum followed by real calculation for crucible furnace according to the specified parameters.
|
|
|
Thermal calculation in design of resistance and induction devices
Krčál, Vít ; Foral, Štěpán (referee) ; Lázničková, Ilona (advisor)
This bachelor’s thesis focuses on thermal calculation of electric heating device and related theory. Selected topics in electric heating technology are explained, followed by the calculation in design of a crucible furnace and its automation using a computer program. The theoretical part first deals with the heat transfer mechanisms and their mathematical description. Further on, the thesis describes how heat is created in resistance and induction heating devices and mentions applications of these types of heating. The main part of the thesis focuses on the thermal calculation of the resistance crucible furnace for aluminium melting. The calculation relates to a cylinder-shaped model of the furnace with determined structure and deals mostly with heat loss, electric power input, thermal efficiency and design of heating elements. The calculation is achieved only in general and it is subsequently automated in Microsoft Office Excel® application. The computer program, which is also a part of the thesis, allows user to change input parameters and see how it affects results of the calculation. In the last chapter, an example of calculation for specific numeric data is presented. The main goal of the thesis is to automate the calculation. That can save some time while calculating and designing a crucible furnace.
|
|
|
Optimalization of indirect resistance heating
Havránek, Miroslav ; Bok, Jaromír (referee) ; Lázničková, Ilona (advisor)
The indirect resistance heating is one of many ways of heating a melting charge. It is used in metallurgy, mostly for melting of soft metals. Its principle is a direct resistance heating in correspondence with the Joule´s law. The principle of indirect resistance heating is in generating of thermal energy in heating element and heat transferring this heat into the melting charge. The theoretical part of this Bachelor Work (the first three chapters) is focused to thermal energy generation and possibility of thermal transmittance. The fourth chapter is devoted to possibility of utilizing of the indirect heating in praxis. The simplest general design and calculation of a pot-type furnace for aluminium melting is done in the fifth chapter. There is a part in this chapter, which deals with the effectivity of the designed pot-type furnace and possibility of heating optimalization in case when indirect heating system is used. The input and calculated parameters of our designed furnace are summed up in the conclusion. There is also comparison of the designed furnace and a furnace readily available on the Czech market and stress on importance of optimalization of heating at indirect heating systems.
|
guest ::
