Soojusõpetuse praktiline ülesanne vabakonvektsiooni uurimiseks
Laen...
Kuupäev
2021
Kättesaadav alates
08.09.2021
Autorid
Ajakirja pealkiri
Ajakirja ISSN
Köite pealkiri
Kirjastaja
Eesti Maaülikool
Abstrakt
Vaba konvektsiooni praktiline uurimine pakub huvi, kuna see võimaldab paremini mõista
soojusülekande protsessi. See on oluline aspekt peamiselt hoonete kütte- ja
ventilatsioonisüsteemide projekteerimisel, samuti muudes valdkondades, kus tehnoloogiate
areng aitab kaasa uute lahenduste otsimisele soojusülekande valdkonnas.
Antud töös püütakse simuleerida konvektsiooniprotsessi silindrikujulise keha ümber ja
võrrelda konvektsiooni intensiivsust vertikaalses ja horisontaalses asendis. Kirjeldatakse
katseseadme arendamise ja valmistamise protsessi. Katseseade koosneb viiest silindrist,
mille kereks on alumiiniumtoru, sisse paigutatud kütteelement vasktraadist, vaheruumala
on täidetud peeneteraliste liivaga. Tehtud katseseeria ja saadud mõõtmistulemuste põhjal
arvutatud konvektsiooni iseloomustavad peamised parameetrid: soojusülekandetegur,
Grashofi, Prandtli ja Nusselti arvud.
Kuna praktiliste testide tulemused osutusid vastuolulisteks, ei olnud võimalik ühemõttelisi
järeldusi teha.Kuid käesolevas töös esitatud materjale, katseseadme kirjeldust, metoodikat
ja tulemuste analüüsi saab kasutada edasises praktilises töös.
Practical research of free convection is interesting as it ensures better understanding of heat transfer processes. It is of crucial importance for the development of heating and ventilation systems in different buildings, as well as for other fields of study where innovative technologies help find new solutions to make heat transfer processes more efficient.In the present research, an attempt was made to simulate convection processes around a cylindrical body and compare convection intensity in the vertical and horizontal positions. Both the development and actual manufacturing of the test device are described in the present paper. The device consists of five cylinders which bodies are made of aluminium pipes with copper wires placed inside them as heating elements and fine sand filling the space between the cylinders. During a series of tests, the required measurements were conducted and the main convection parameters, i.e. heat transfer coefficient, Grashof, Prandtl, and Nusselt numbers, were calculated. Due to the fact that test results were relatively controversial, it was impossible to draw uniform conclusions. However, the description of the test device, the methods applied and the analysis of the results can be used for further research and practical purposes.
Practical research of free convection is interesting as it ensures better understanding of heat transfer processes. It is of crucial importance for the development of heating and ventilation systems in different buildings, as well as for other fields of study where innovative technologies help find new solutions to make heat transfer processes more efficient.In the present research, an attempt was made to simulate convection processes around a cylindrical body and compare convection intensity in the vertical and horizontal positions. Both the development and actual manufacturing of the test device are described in the present paper. The device consists of five cylinders which bodies are made of aluminium pipes with copper wires placed inside them as heating elements and fine sand filling the space between the cylinders. During a series of tests, the required measurements were conducted and the main convection parameters, i.e. heat transfer coefficient, Grashof, Prandtl, and Nusselt numbers, were calculated. Due to the fact that test results were relatively controversial, it was impossible to draw uniform conclusions. However, the description of the test device, the methods applied and the analysis of the results can be used for further research and practical purposes.
Kirjeldus
Bakalaureusetöö
Tehnika ja tehnoloogia õppekaval
Märksõnad
bakalaureusetööd, soojusülekanne, soojusülekandetegur, soojusvool, laminaarne voolamine