Dopolnitev računalniškega programa za račun vodnega udara s pogojem kavitacije : diplomska naloga

Anzeljc, Blaž (author), Četina, Matjaž (mentor), Bergant, Anton (comentor)

Sprememba pretočne hitrosti povzroči nihanje tlakov v cevnih sistemih, kjer je tok kapljevine pod tlakom. Pri tem je kontinuiteta kapljevine prekinjena (pretrganje kapljevinskega stebra), ko se tlak v sistemu zniža na nivo parnega tlaka kapljevine. Za potrebe diplomske naloge je bil nadgrajen računalniški program za račun vodnega udara, ki ne upošteva procesa uparevanja kapljevine pri njenem parnem tlaku, v diskretni parni kavitacijski model, kjer je pogoj pretrganja kapljevinskega stebra upoštevan. Poleg prvotne nadgradnje je bil program dodatno izpopolnjen z metodo časovnega zamika nastanka in zrušitve mehurja pare. Validacija treh različic programa, ki je bila izvedena s primerjavo med numeričnimi rezultati in rezultati meritev v laboratoriju, je jasno pokazala prednosti izboljšanega numeričnega modela.

• Language: Slovenian
• Keywords: gradbeništvo, diplomska naloga, UNI, vodni udar, parna kavitacija, pretrganje kapljevinskega stebra, tlačni pulz, diskretni parni kavitacijski model, metoda časovnega zamika, validacija
• Work type: Undergraduate thesis
• Typology: 2.11 - Undergraduate Thesis
• Organization: FGG - Faculty of Civil and Geodetic Engineering
• Place of publishing: Ljubljana
• Publisher: [B. Anzeljc]
• Year: 2016
• Number of pages: X, 49 str.
• PID: 20.500.12556/RUL-86100
• UDC: 532.542:532.528(043.2)
• COBISS.SI-ID: 7752033
• Publication date in RUL: 14.11.2016

Secondary language

• Language: English
• Title: Upgrade of computer program for water hammer calculation with cavitation condition

Abstract

A change of flow velocity induces pressure fluctuations in piping systems, where flow of a liquid is under pressure. Liquid column separation occurs when the pressure drops to the level of the liquid vapour pressure. For the requirements of the graduation thesis, the computer program for water hammer calculation, which does not take into account a vaporatization process at the liquid vapour pressure, was upgraded to the discrete vapour cavity model, where the condition of the liquid column separation is taken into account. In addition to the primary upgrade, the program was further improved with the method of improved timing of opening and collapse of a vapour cavity. The validation of three versions of the program, which was carried out with the comparison between numerical results and results from laboratory measurements, clearly showed advantages of the improved numerical model.

• Keywords: graduation thesis, water hammer, vaporous cavitation, liquid column separation, pressure pulse, discrete vapour cavity model, method of improved timing, validation