However, accurate and reproducible THz measurements of aqueous solutions, largely represented in life sciences, remain difficult. TeraHertz (THz) spectroscopy is becoming an alternative way to probe biological interactions in real-time conditions. The integrated test rig achieved electric power generation of 30 W at 200,000 rpm, 50% of the design rotational speed. In the combustor, we used liquefied petroleum gas as the main fuel and kerosene as the ignition fuel and partially as the main fuel during the boost operation. We employed a radial-thrust integral metal-mesh bumper air foil bearing with which we obtained the design rotational speed of 400,000 rpm in a standalone motoring test. We controlled a motor-generator using an electric controller in fixed speed mode and guided the rotational speed according to the start-up sequence. Here, we describe our development and testing of a new integrated test rig to measure the performance of electric-power generation during self-sustaining and boosting operations.
In a previous study, we used an integrated test rig to examine the feasibility of start-up and self-sustaining capabilities. System specifications include a design rotational speed of 400,000 rpm, a compressor ratio of 3:1, and a turbine inlet temperature of 1200 K. We experimentally investigate the feasibility of a 500-W class ultra-micro gas turbine power generator. Finally, we presented experimental data for the flow field behind the shock wave from measurements of the Mach wave angle which shows globally decreasing flow Mach numbers due to viscous wall effects. The data are also compared with the empirical shock attenuation models proposed by Zeitoun (Phys Fluids 27(1):011701, 2015) and Deshpande and Puranik (Shock Waves 26(4):465–475, 2016), where better agreement is observed. We found that these models are inadequate to predict the observed data, owing to the presence of fully developed flow which violates the basic assumption of these models. Then, we compared our experimental results for different channel widths, lengths, and shock wave velocities with the analytical model for shock attenuation proposed by Russell (J Fluid Mech 27(2):305–314, 1967), which assumes laminar flow, and by Mirels (Attenuation in a shock tube due to unsteady-boundary-layer action, NACA Report 1333, 1957) for turbulent flow. In this paper, we present the experimental technique and the relevant data treatment we have used to increase the sensitivity of shock wave detection. This transparent facility, with a cross section ranging from \(1\,\hbox \), allowed for the use of high-speed schlieren videography to visualize the propagation of a shock wave within the entire micro-channel and to quantify velocity attenuation of the wave due to wall effects.
This work presents optical measurements of shock wave attenuation in a glass micro-channel.