Title: An experimental investigation towards calibration of a shock tube and stagnation heat flux determination
Authors: Sumit Agarwal; Niranjan Sahoo
Addresses: Department of Mechanical Engineering, Indian Institute of Technology Guwahati, Assam-781039, India ' Department of Mechanical Engineering, Indian Institute of Technology Guwahati, Assam-781039, India
Abstract: This paper aims at comprehensive investigations towards design and installation of a moderate size shock tube (7 m long having an inner diameter of 55 mm, 20 mm thickness) and its experimental calibration through comparative parametric study. Necessary instrumentations are incorporated for measuring shock speeds and pressure rise across primary as well as reflected shock, obtained using nitrogen/helium as driver gas. The experimental evidence shows reasonable agreement between theoretical (one-dimensional shock tube relations) results. Further, an E-type coaxial surface junction thermocouple (CSJT) has been prepared in the laboratory and oil-bath calibration experiment gives its 'sensitivity'. Measurement of instantaneous surface temperature rise and subsequent stagnation heat flux are obtained using CSJT mounted on a specially-designed end-flange. The thermocouple noted a maximum rise of temperature of 7,800 K, marked as a characteristic constant of the sensor; since it is found to be independent of the magnitude of the step change in temperature.
Keywords: shock tube; primary shock; reflected shock; coaxial surface junction thermocouple; CSJT; stagnation heat flux.
International Journal of Aerodynamics, 2018 Vol.6 No.1, pp.18 - 40
Accepted: 24 Oct 2017
Published online: 09 Feb 2018 *