Vpliv salicilne kisline na dinamiko kavitacijskega toka v mikrokanalih

Suljkanović, Isa (author), Dular, Matevž (mentor)

Salicilna kislina lahko umirja dinamično aktivnost kavitacije. Obenem je možno meriti dinamično aktivnost preko produktov salicilne kisline in OH radikalov. Slednji nastanejo ob implozijah kavitacijskih mehurčkov. V raziskovalnem delu smo spreminjali koncentracijo salicilne kisline in zraka. Pripravili smo aparaturo, ki je črpala destilirano vodo s salicilno kislino skozi Venturijevo cev, kjer je na ožini cevi nastajala kavitacija. To mesto smo opazovali s hitro kamero. Iz slik posnetih s hitro kamero smo s pomočjo programa v Matlabu naredili povprečne slike nahajanja kavitacije in njene standardne deviacije. Iz obdelanih slik smo lahko razbrali v katerih raztopinah je bila dinamična aktivnost večja. V drugem delu eksperimenta smo vzorce salicilne kisline analizirali s HPLC metodo in določali vsebnost produktov 2,3-DHBA, 2,5-DHBA in katehola, kot posledica reakcije salicilne kisline in OH radikalov. Skušali smo vzpostaviti korelacijo med vizualnimi opažanji in rezultati z analize. Ugotovili smo, da visoka dinamična aktivnost na slikah ne pomeni nujno nastanek večje količine radikalov, saj ti lahko rekombinirajo v začetno stanje, preden reagirajo s salicilno kislino. Poleg tega večja koncentracija salicilne kisline ni vedno ponudila večji izkoristek nastalih produktov. Pri vizualizaciji smo opazili najbolj dinamično aktivne slike standardnih deviacij prav pri višji koncentraciji salicilne kisline, kar ni bilo pogosto pri prejšnjih podobnih eksperimentih.

• Language: Slovenian
• Keywords: kavitacija, salicilna kislina, hitra kamera, radikali, dinamična aktivnost
• Work type: Bachelor thesis/paper
• Typology: 2.11 - Undergraduate Thesis
• Organization: FKKT - Faculty of Chemistry and Chemical Technology
• Year: 2021
• PID: 20.500.12556/RUL-129740
• COBISS.SI-ID: 79579395
• Publication date in RUL: 07.09.2021

Secondary language

• Language: English
• Title: Effect of salicylic acid on dinamics of cavitating flow in microchannels

Abstract

Salicylic acid can ease the dynamic activity of cavitation. Furthermore, it is possible to measure dynamic activity trough the products of OH radical reactions with salicylic acid. With radicals forming when cavitation bubbles implode, releasing big amounts of energy. In the experiment we were changing the concentration of salicylic acid and air in the solution. An apparatus was assembled that pumped distilled water through the Venturi nozzle, where cavitation formed in the constricted area. This was also the part of the nozzle that was filmed with a fast camera. With a program in Matlab we processed the images taken with the camera to make pictures of cavitation average location and standard deviation. From these pictures it was easier to distinguish in which solutions the dynamic activity was higher. In the second part of the experiment we analyzed the samples of salicylic acid with HPLC method to determine the concentrations of 2,3-DHBA, 2,5-DHBA and catechol as they were the products of salicylic acid reacting with OH radical. We wanted to see if there is a correlation between the amounts of products that were yielded with the dynamic activity seen on the pictures made in Matlab. It was noticed that high dynamic activity on pictures did not lead to more products. Radicals could have rearranged before salicylic acid had the chance to trap them. Also higher concentration of salicylic acid didn't always yield more products. In the visualization part it was also noted that most dynamical active pictures were actually those with higher salicylic acid concentrations, which wasn't the case in some of previous similar experiments.

• Keywords: cavitation, salicylic acid, fast camera, radicals, dynamic activity