Razvoj etalonskog mjernog sustava za male protoke plina

doctoral thesis

• Title (english): Development of standard measurement system for low gas flow rate
• Author: Berislav Pavlović
• Mentor: Davor Zvizdić (mentor)
• Committee member: Ivan Galaso (predsjednik povjerenstva)
• Committee member: Davor Zvizdić (član povjerenstva)
• Committee member: Miljenko Šunić (član povjerenstva)
• Granter: University of Zagreb; Faculty of Mechanical Engineering and Naval Architecture; Zagreb
• Defense date and country: 2011-01-18, Croatia
• Scientific / art field, discipline and subdiscipline: TECHNICAL SCIENCES; Mechanical Engineering; Process Energy Engineering
• Universal decimal classification (UDC): 622 - Mining ; 53 - Physics

Abstract

U radu je prikazan sustav za umjeravanje mjerila protoka odnosno volumena korištenjem metode vaganja, odnosno metode istiskivanja kapljevine preko osnovnih SI jedinica mase i vremena. Razvijeni model sljediv je s etalonima mase Physikalisch-Technische Bundesanstalta, Njemačka. Model je provjeren eksperimentalno preko usporedbe s prijenosnim etalonima protoka sljedivih prema Physikalisch-Technische Bundesanstalt, Njemačka. Prikazan je osnovni model koji opisuje fizikalna zbivanja tijekom mjerenja. Model polazi od metode istiskivanja kapljevine iz zatvorenog spremnika. Tijekom istakanja kapljevine iz zatvorenog spremnika volumen koji je nastao istakanjem kapljevine ispunjava zrak koji dostrujava u zatvoreni spremnik. Budući da je poznata gustoća kapljevine, volumen istisnute kapljevine odnosno dostrujanog zraka se određuje vaganjem. Dani su i osnovni podaci o drugim metodama mjerenja protoka plinova. U eksperimentalnom dijelu rada mjerenjima su određene karakteristike sustava, provedeno je umjeravanje prijenosnog mjerila protoka Rombach NB2, te je umjereno ispitno zvono. Prikazan je proračun mjerne nesigurnosti, te su navedene procedure mjerenja u pojedinim fazama izrade rada. Nadalje, provedena su usporedbena mjerenja s prijenosnim etalonskim mjerilima protoka NB2 i NB15. Ova mjerenja su obuhvaćala usporedbu s ispitnim zvonom. Opisan je osnovni ispitni sustav s glavnim komponentama koji pokriva područje protoka do 1,4 m 3 /h. Prikazan je matematički model za određivanje pogreške pokazivanja ispitivanog mjerila protoka i nazivne vrijednosti segmenta volumena ispitnog zvona kao i procjena mjerne nesigurnosti. Prikazani su rezultati mjerenja i proračun mjerne nesigurnosti za karakteristične uvjete rada. Dan je prikaz dominantnih komponenata koje utječu na mjernu nesigurnost. Prikazano je i odstupanje osnovnog ispitnog sustava i ispitnog zvona u odnosu na rezultate umjeravanja prijenosnih etalona provedenih u Njemačkoj određivanjem faktora odstupanja normaliziranog u odnosu na mjernu nesigurnost.

Abstract (english)

A system for calibration of gas flow meters and volume meters by weighing method is presented, i.e. liquid displacement method by using main SI units for mass and time. The model developed is traceable to mass standard of Physikalisch-Technische Bundesanstalt, Germany. The model is validated by comparison with the transfer standards traceable to gas flow standards of Physikalisch-Technische Bundesanstalt, Germany. The main model which describes the phisical process of measurement is presented. The model is based on displacement of liquid from closed container. During the displacement of liquid, the volume of oil leaving the container is replaced by the same volume of air. Since the density of oil is known, the volume of oil displaced, ie. air which has flown into the container is determined by weighing. Other methods for gas flow measurements are briefly reported as well. In experimental part of research the main characteristics of the system are determined, calibration of wet gas flow meter Rombach NB2 and bell prover is performed. A calculation of measurement uncertainty is presented and procedures of measurements in certain stages of research are given. Furthermore, a comparison of bell prover with transfer gas flow standards NB2 and NB15 was performed and presented. The basic testing system with main components which working range up to 1,4 m 3 /h is described. A mathematical model for determining relative deviation of meter under test and volume of segments of bell prover as well as estimation of measurement uncertainty are presented. The results of measurement and calculation of measurement uncertainty for characteristic conditions of use are presented. An illustration of components which have dominant influence on measurement uncertainty is given. A deviation of basic testing system and a bell prover compared with the results of calibration of transfer standards performed in Germany is given by obtaining the deviation factor normalised with measurement uncertainty.

• Keywords: mjerilo protoka plina; metoda istiskivanja kapljevine; mjerna nesigurnost
• Keywords (english): gas flow measurement device; liquid displacement method; measurement
• Language: croatian
• URN:NBN: urn:nbn:hr:235:010342
• Study programme: Title: Mechanical Engineering and Naval Architecture; Study programme type: university; Study level: postgraduate; Academic / professional title: doktor/doktorica znanosti, područje tehničkih znanosti (doktor/doktorica znanosti, područje tehničkih znanosti)
• Type of resource: Text
• File origin: Born digital
• Access conditions: Open access
• Created on: 2020-05-15 17:03:59