Abstract
Schlieren visualization of the plume ejected from the microgas turbine nozzle was conducted to understand infrared signal characteristics of various shapes of the exhaust nozzle. At the same time, the precise temperature distribution and infrared signal measurement were performed and compared. The maximum thrust of the microgas turbine used in the experiment is 230 N, the maximum speed of revolution is 108,500 rpm, and the maximum exhaust gas temperature is 750 °C. Seven nozzles were used for this experiment which included a cone nozzle, five square nozzles with aspect ratios (AR) ranging from 1 to 5 and an S-shaped nozzle with aspect ratio 6. The infrared signal emitted from the exhaust plume decreased as the aspect ratio increased. Schlieren flow visualization images show that cone nozzle had a uniform flow pattern, while square nozzle had a bright triangle pattern in the dispersed plume. As the aspect ratio of square nozzles increased, a bright triangle pattern reduced in size. On comparing Schlieren visualization with the temperature distribution, it can be understood that the triangular shape of core plume plays a major role in the temperature diffusion with the surrounding air. Based on the temperature distribution and the results of the Schlieren visualization, three types of exhaust plume models are suggested. These three models are homogenous plume, intermediate plume and two-dimensional plume with hot core, which correspond to the cone nozzle, the AR2 square nozzle and AR5 square nozzle, respectively.
Graphic abstract
Similar content being viewed by others
References
An CH, Kang DW, Baek ST, Myong RS (2016) Analysis of plume infrared signatures of S-shaped nozzle configurations of aerial vehicle. J Aircr 53(6):1768–1778
Choi SM, Myong S, Myong RS, Kim W (2019) Experimental investigation of infrared signal characteristics in a micro-turbojet engine. Aeronaut J 123(1261):340–355
Decher R (2004) Infrared emission from turbofans with high aspect ratio nozzle. J Propul Power 20(3):527–532
Dix J, Saddington AJ, Knowles K, Richardson MA (2005) Infrared signature reduction study on a small-scale jet engine. Aeronaut J 109(1092):83–88
Gu BC, Baek SW, Jegal HW, Choi SM, Kim WC (2017) Infrared signature characteristic of a microturbine engine exhaust plume. Infrared Phys Technol 86:11–22
Mahulikar SP, Rao GA, Sane SK, Marathe AG (2005) Aircraft plume infrared signature in non-afterburning mode. J Thermophys heat Transf 19(3):413–415
Mahulikar SP, Rao GA, Kolhe PS (2006) Infrared signature of low flying aircraft and their rear fuselage skin’s emissivity optimization. J Aircr 43(1):226–232
Mahulikar SP, Sonawane HR, Rao GA (2007) Infrared signature studies of aerospace vehicles. Prog Aerosp Sci 43:218–245
Settles GS (2001) Schlieren and shadowgraph techniques. Springer, Berlin
Varney GE (1979) Infrared signature measurement technique and simulation methods for aircraft survivability. In: AIAA/SAE/ASME 15th joint propulsion conference
Author information
Authors and Affiliations
Corresponding author
Additional information
Publisher's Note
Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.
Rights and permissions
About this article
Cite this article
Choi, S.M., Lee, J.S., Myong, R.S. et al. Schlieren visualization of micro gas turbine exhaust plume with different shapes of nozzle. J Vis 23, 565–576 (2020). https://doi.org/10.1007/s12650-020-00648-9
Received:
Revised:
Accepted:
Published:
Issue Date:
DOI: https://doi.org/10.1007/s12650-020-00648-9