The quantification of the flow irreversibilities is crucial to developing future turbomachinery. Traditionally, design correlations and efficiencies are based on comparisons to isentropic relations to quantify the deviation from an “ideal” case. However, isentropic relations typically assume one-dimensional adiabatic flow, representing a significant departure from the actual situation in turbines operating with large levels of heat transfer. In this paper, the aerothermal losses and power generation in reversible processes are derived for three-dimensional compressible flow […]
Archives: Publications
Archives: Publications
Characterizing the time scales of starting in supersonic passages is essential for future aerospace propulsion systems, such as supersonic intakes, Rotating Detonation Engines, and power generation systems based on Organic Rankine Cycles. This paper first compares 2D URANS results with 1D Euler results to identify the equations that govern the acceleration and deceleration of the strong shock during the starting process’s time evolution. Secondly, we characterized the effect of the frequency of pulsating flows on […]
Archives: Publications
To achieve an optimal matching between the turbocharger and internal combustion engine over a wide range of the engine operation map, their complex interaction is commonly analyzed by means of transient one-dimensional modeling. The pulsating flow of the engine exhaust gases causes high variations of turbine inlet mass flow, total pressure, and total temperature. This pushes the turbocharger turbine operation towards extreme off-design conditions. Hence, wide turbine operation maps are required as input for the […]
Archives: Publications
Over the past few decades, the aerodynamic improvements of turbocharger turbines contributed significantly to the overall efficiency augmentation and the advancements in the downsizing of internal combustion engines. Due to the compact size of automotive turbochargers, the experimental measurement of the complex internal aerodynamics has been insufficiently studied. Hence, turbine designs mostly rely on the results of numerical simulations and the validation of zero-dimensional parameters as efficiency and reduced mass flow. To push the aerodynamic […]
Archives: Publications
New compact engine architectures such as pressure gain combustion require ad hoc turbomachinery to ensure an adequate range of operation with high performance. A critical factor for supersonic turbines is to ensure the starting of the flow passages, which limits the flow turning and airfoil thickness. Radial outflow turbines inherently increase the cross section along the flow path, which holds great potential for high turning of supersonic flow with a low stage number and guarantees […]