Analiza naprezanja dimnocijevnog parnog kotla metodom konačnih elemenata

professional thesis

• Author: Jura Tomorad
• Mentor: Ivica Skozrit (mentor)
• Committee member: Zdenko Tonković (predsjednik povjerenstva)
• Committee member: Ivica Skozrit (član povjerenstva)
• Committee member: Martina Lovrenić-Jugović (član povjerenstva)
• Granter: University of Zagreb; Faculty of Mechanical Engineering and Naval Architecture; Zagreb
• Defense date and country: 2023-07-14, Croatia
• Scientific / art field, discipline and subdiscipline: TECHNICAL SCIENCES; Mechanical Engineering

Abstract

U radu je izvršena analiza naprezanja dimnocijevnog parnog kotla pri radnom
opterećenju i u slučaju tlačne probe pomoću metode konačnih elemenata. Model kotla izrađen
je u programskom paketu Autodesk Inventor i potom analiziran u Inventor Nastran-u. Analiza
je napravljena prema postojećoj izvedbi dimnocijevnog parnog kotla konstruiranog prema
HRN EN 12953-3:2016. Prije provedbe numeričke analize, potvrđena je ispravnost korištenja
softvera verifikacijom svih upotrijebljenih konačnih elemenata na pojednostavljenom
primjeru tankostijenog cilindričnog spremnika s ravnim dnom opterećenog unutarnjim
tlakom. Provedena je usporedba rezultata dobivenih metodom konačnih elemenata i
analitičkim proračunom prema referenciranoj literaturi.
Numerička analiza kotla obuhvaća provedbu linearne analize prijenosa topline,
linearne statičke analize, definiranje rubnih uvjeta opterećenja unutarnjim konstantnim
tlakom, hidrostatskim tlakom, težinom i temperaturnog opterećenja te rubnih uvjeta veze s
okolinom. Obrađena je i problematika povezivanja tetraedarskih konačnih elemenata drugog
reda s grednim elementima prvog reda pomoću idealno krutih veza.
Za proračun čvrstoće primijenjen je analitički pristup konstruiranju definiran aneksom
C norme HRN EN 13445-3:2021 pod nazivom metoda kategorizacije naprezanja. Za
postizanje sigurnosti u dobivene rezultate korišten je postojeći proračun prema formulama
izrađen prema HRN EN 12953-3:2016 dostupan u projektnoj dokumentaciji kotla. U ovom
radu razvijena je metodologija proračuna prema navedenoj normi usklađena s opcijama i
izlaznim podacima dostupnim u korištenom programskom paketu. Provedena je linearizacija
naprezanja na kritičnim lokacijama u kotlu te na kraju i evaluacija naprezanja čitave
konstrukcije prema zadanoj normi.

Abstract (english)

In this thesis, the stress analysis of the shell steam boiler in the normal operating load
case and in the testing load case was performed using the finite element method. Model of the
boiler was created in Autodesk Inventor and then analysed in Inventor Nastran. The analysis
was made according to the existing version of shell boiler designed according to HRN EN
12953-3:2016. Before carrying out the numerical analysis, the applicability of using the
software was confirmed by verifying all used finite elements on a simplified example of a
thin-walled cylindrical pressure vessel with a flat bottom with internal pressure load.
Comparison of the results obtained by the finite element method and analytical calculation
according to the referenced literature was carried out.
Numerical analysis of the boiler includes the implementation of linear steady-state
heat transfer analysis, linear static analysis, definition of boundary conditions of constant
internal pressure, hydrostatic pressure, weight and temperature load, and boundary conditions
of connection with the environment. The issue of connecting parabolic solid finite elements
(tetrahedrons) with linear line elements (beams) by means of rigid body connectors (RBE2) is
also addressed.
For strenght calculation, design by analysis approach defined by Annex C of the HRN
EN 13445-3:2021, called the method based on stress categories, was applied. To achieve
certainty in the obtained results, the existing design by formulae strenght calculation carried
out according to HRN EN 12953-3:2016 and available in the project documentation of the
boiler was used. In this paper, a calculation methodology was developed according to the
specified standard, harmonized with the options and output data available in the used finite
element analysis software. Stress linearisation was performed at critical locations in the
boiler, and finally stress evaluation of the entire structure according to the given annex.

• Keywords: dimnocijevni parni kotao; tlačna oprema; metoda konačnih elemenata; Inventor Nastran; proračun čvrstoće; analitičko konstruiranje; metoda kategorizacije naprezanja; linearizacija naprezanja; aneks C norme HRN EN 13445-3:2021; HRN EN 12953-3:2016
• Keywords (english): shell boiler; steam boiler; pressure equipment; finite element method; Inventor Nastran; strenght calculation; design by analysis; method based on stress categories; stress linearisation; HRN EN 13445-3:2021 Annex C; HRN EN 12953-3:2016
• Language: croatian
• URN:NBN: urn:nbn:hr:235:175829
• Study programme: Title: Mechanical Engineering and Naval Architecture - specialist; Study programme type: university; Study level: postgraduate specialist; Academic / professional title: sveučilišni/a specijalist/specijalistica strojarstva i brodogradnje (sveučilišni/a specijalist/specijalistica strojarstva i brodogradnje)
• Type of resource: Text
• File origin: Born digital
• Access conditions: Open access
• Created on: 2023-07-21 09:43:13