Schlieren Imaging of Microthruster Exhausts for Qualitative and Quantitative Analysis
2012 (English)In: Measurement science and technology, ISSN 0957-0233, E-ISSN 1361-6501, Vol. 23, no 8, 085403- p.Article in journal (Refereed) Published
Abstract. Schlieren imaging is a method used to visualize diﬀerences in refractiveindex within a medium. It is a powerful and straightforward tool for sensitiveand high-resolution visualization of, e.g., gas ﬂows. Here, heated cold gasmicrothrusters were studied with this technique. The thrusters are manufacturedusing microelectromechanical systems technology, and measure 22×22×0.85 mm. Thenozzles are approximately 20 µm wide at the throat, and 350 µm wide at the exit.Through these studies, veriﬁcation of the functionality of the thrusters, and directvisualization and of the thruster exhausts was possible. At atmospheric pressure,slipping of the exhaust was observed, due to severe overexpansion of the nozzle. Invacuum (3 kPa), the exhaust was imaged while feed pressure was varied from 100 to450 kPa. The nozzle was overexpanded, and the ﬂow was seen to be supersonic. Theshock cell period was linearly dependent on feed pressure, ranging from 320 to 610 µm.With activated heaters, the shock cell separation increased. The eﬀect of the heaterswas more prominent at low feed pressure, and an increase in speciﬁc impulse of 20%was calculated. It was also shown that schlieren imaging can be used to detect leaks,making it a valuable, safe, and noninvasive aid in quality control of the thrusters.
Place, publisher, year, edition, pages
Institute of Physics (IOP), 2012. Vol. 23, no 8, 085403- p.
Schlieren imaging, microthrusters, MEMS, shock cells
Other Engineering and Technologies not elsewhere specified
Research subject Engineering Science with specialization in Microsystems Technology
IdentifiersURN: urn:nbn:se:uu:diva-186252DOI: 10.1088/0957-0233/23/8/085403ISI: 000306366600039OAI: oai:DiVA.org:uu-186252DiVA: diva2:572764