Chiranjeev Kalra

Investigation of Filtered Rayleigh Scattering Techniques for Rig Testing Diagnostics

A laboratory investigation of Filtered Rayleigh Scattering (FRS) techniques for high-resolution and high-accuracy temperature measurements in rig tests with high pressures and temperatures and combustion is presented.Imaging techniques based on filtered Rayleigh scattering have the potential for two-dimensional (2D) and near wall measurement of gas velocity and temperature fields among other properties. For gas temperature measurements, laser Rayleigh scattering from gas molecules are typically captured with an ICCD camera and temperature can be inferred from the number density measured from the image intensities. The accuracy challenges associated with property spatial variations, gas composition, and pressure and temperature conditions are investigated for the rig test environments.Representative examples including mixing layer, jet and vortex flows and flame and combustion tests are presented.Copyright

Development of 1 MWe Supercritical CO2 Test Loop

Recent studies have demonstrated that sCO2 in a closed-loop recompression. Brayton cycle offers equivalent or higher cycle efficiency when compared with supercritical- or superheated-steam cycles at temperatures relevant for CSP applications. With funding under the SunShot initiative, the authors are developing a high-efficiency sCO2 turbo-expander for the solar power plant duty cycle profile and novel compact heat exchangers for the sCO2 Brayton cycle. However, no test loop exists to test the turbine and heat exchangers under development. Therefore, a customized test loop is being developed at Southwest Research Institute that will accommodate the full test pressures (80 to 280 bar) and temperatures (45 to 700°C) of the proposed Brayton cycle. The paper describes the design methodology to predict the pipe flow behavior and thermal growths as well as material selection. A customized natural gas fired heater is currently being designed, since no heater like it is available currently.Copyright

Design of an Air Dynamometer for Direct Connection to the SunShot SCO2 Turbine Expander Shaft

In conjunction with the SunShot program to develop a supercritical CO2 turbine expander, an air dynamometer was developed to absorb the power of the SCO2 turbine during development testing. The dynamometer is unique in that it is directly mounted to the shaft of the turbine expander replacing the associated compressor coupling during the test campaign. It is able to replicate both the load of the compressor as well as the rotordynamic qualities of the compressor coupling all without the need for additional bearings, casing, or larger skid. The dynamometer consists of a single-stage centrifugal air compressor ingesting ambient air. To maximize turn-down and minimize weight, the impeller diameter and flow coefficient were optimized along with the design of the loop throttle valves. The detailed aerodynamic, rotordynamic, and mechanical design for the dynamometer is presented. The aerodynamic methodology to minimize unsteady forces transmitted to the turbine will also be reviewed.Copyright