Effects of dimensional size and surface roughness on service performance for a micro Laval nozzle. (23rd March 2017)

• Record Type: Journal Article
• Authors: Cai, Yukui; Liu, Zhanqiang; Shi, Zhenyu
• Is Part Of: Journal of micromechanics and microengineering. Volume 27:Number 5(2017:May)
• Publication Date: 2017-03-23
• Subjects: Laval nozzle -- size effect -- surface roughness -- ball-end milling; Microelectromechanical systems -- Periodicals; Micromechanics -- Periodicals; 621.38105
• DOI: 10.1088/1361-6439/aa6552
• Languages: English
• ISSNs: 0960-1317

Abstract

Abstract: Nozzles with large and small dimensions are widely used in various industries. The main objective of this research is to investigate the effects of dimensional size and surface roughness on the service performance of a micro Laval nozzle. The variation of nozzle service performance from the conventional macro to micro scale is presented in this paper. This shows that the dimensional nozzle size has a serious effect on the nozzle gas flow friction. With the decrease of nozzle size, the velocity performance and thrust performance deteriorate. The micro nozzle performance has less sensitivity to the variation of surface roughness than the large scale nozzle does. Surface quality improvement and burr prevention technologies are proposed to reduce the friction effect on the micro nozzle performance. A novel process is then developed to control and depress the burr generation during micro nozzle machining. The polymethyl-methacrylate as a coating material is coated on the rough machined surface before finish machining. Finally, the micro nozzle with a throat diameter of 1 mm is machined successfully. Thrust test results show that the implement and application of this machining process benefit the service performance improvement of the micro nozzle.