Določanje homogenosti in stabilnosti tokovnega polja v merilni sekciji vetrovnika

Hrušovar, Nika (author), Bobovnik, Gregor (mentor), Kutin, Jože (comentor)

Homogenost in stabilnost hitrostnega polja v merilni sekciji vetrovnika imata velik vpliv na rezultate merjenja hitrosti zraka v vetrovniku. V okviru magistrskega dela smo postavili in opisali novo merilno progo z dvo-komponentnim LDA merilnikom in vetrovnikom. Posebno pozornost smo posvetili popisu funkcij v nadzornem programu. Dobljeni rezultati kažejo, da je stabilnost pri hitrostih zraka med 10 in 30 m/s manj kot 0,2 %, pri hitrosti zraka 0,3 m/s pa je bila izračunana stabilnost več kot 10 %. Karakterizacija hitrostnih profilov je pokazala spreminjanje hitrostnega profila vzdolž merilne sekcije, kar je posledica geometrijske razširitve. Homogenost hitrostnega polja smo izračunali za različne velikosti pretočnih prerezov in različne hitrosti. Izračunana homogenost je manj kot 1,2 %, razen pri majhnih hitrostih (npr. 0,3 m/s), kjer znaša 3,8 %. Iz meritev homogenosti ne moremo izločiti vpliva nestabilnosti. Z izvedbo dodatne meritve smo opozorili tudi na upoštevanje zastojnega učinka pri umerjanju v polju pred merilnikom v merilni sekciji.

• Language: Slovenian
• Keywords: Merjenje hitrosti, Laser Dopplerjev anemometer (LDA), hitrostni profil, vetrovnik, homogenost, stabilnost
• Work type: Master's thesis/paper
• Typology: 2.09 - Master's Thesis
• Organization: FS - Faculty of Mechanical Engineering
• Place of publishing: Ljubljana
• Publisher: [N. Hrušovar]
• Year: 2019
• Number of pages: XXII, [56] str.
• PID: 20.500.12556/RUL-109844
• UDC: 533.6.071:551.508.54(043.2)
• COBISS.SI-ID: 16919067
• Publication date in RUL: 09.09.2019

HRUŠOVAR, Nika, 2019, Določanje homogenosti in stabilnosti tokovnega polja v merilni sekciji vetrovnika [online]. Master’s thesis. Ljubljana : N. Hrušovar. [Accessed 30 March 2025]. Retrieved from: https://repozitorij.uni-lj.si/IzpisGradiva.php?lang=eng&id=109844

Secondary language

• Language: English
• Title: Assessment of homogeneity and stability of the flow field in the measuring section of the wind tunnel

Abstract

The homogeneity and stability of the velocity field in the measuring section of the wind tunnel have a significant influence on the results of air velocity measurements in the wind tunnel. In this master's thesis, we set up and described a new measuring system with the two-component LDA and the wind tunnel. Special attention was devoted to the description of the functions in the control program. The results show that the stability of the air velocity between 10 and 30 m/s is less than 0.2 % and for lower velocities higher than 10 %. Characterization of velocity profiles showed a change in velocity profile along the measurement section resulting from the geometric extension. The homogeneity of the velocity field was calculated for different cross-sectional areas and different velocities. The experimental data show that the homogeneity is less than 1.2 %, except at low speeds (e.g. 0.3 m / s), where it is equal to 3.8 %. The impact of the instability cannot be excluded from homogeneity measurements. By performing an additional measurement, we also noted that the blockage effect occurs in the field upstream of the anemometer in the measuring section.

• Keywords: Velocity measurement, Lasser Doppler anemometer, velocity profile, wind tunnel, homogeneity, stability