The Effect of Unsteady Inlet Conditions on a Supersonic Turbine

ABSTRACT

Supersonic axial turbines which are integrated with continuous detonation combustors will encounter the high-frequency and high-speed flow of the combustor exhaust. To ensure started flow and efficient work extraction, supersonic passages must be able to ingest the incoming supersonic flow. Designing supersonic turbines that are able to extract work efficiently requires a good understanding of the characteristics of the supersonic turbine exposed to fluctuating, supersonic flow. The results of a numerical study with two-dimensional unsteady Reynolds-averaged Navier-Stokes (URANS) simulations will be used to explain the effects of unsteady supersonic inlet conditions on a supersonic bladed passage and turbine stage.

Marc Ng received his B.Eng in Mechanical Engineering from National University of Singapore in 2020 and thereafter began working at TL@NUS in the Propulsion group. He is also an M.Eng student at NUS working on supersonic turbine design using CFD.

Improved Riemann-SPH Method & its Applications in Multiphase Flows

ABSTRACT

Multiphase flow is a common phenomenon in the field of naval architecture and marine engineering, and it always involves large fluid deformation, multiphase interface mixing, nonlinear fluid-structure interaction effect and other problems. As the most widely used meshless numerical method, the smooth particle hydrodynamics (SPH) method has obvious advantages in dealing with fluid splashing, large deformation, and moving interfaces, and thus is an advantageous method for solving multiphase flow problems. However, the traditional SPH still faces some challenges for multiphase flows, such as the inability to consider the true compressibility of the gas phase, the presence of some non-physical oscillations in pressure field, and the lack of robust compressible formulations. To deal with these problems, based on the Riemann SPH method, we propose some numerical improvements, including a low-dissipation SPH limiter, a new WENO reconstruction in SPH, and an accurate axisymmetric SPH scheme for strongly-compressible flows. Then, some typical numerical tests are performed to validate the accuracy of the proposed SPH methods. Finally, the proposed SPH methods are applied to some typical multiphase flow problems such as water entries, ditching of seaplane and high-pressure bubble dynamics.

Wang Pingping, Lecturer of Harbin Engineering University. He obtained his Bachelor's and PhD degrees from Harbin Engineering University in 2016 and 2022, respectively. His main research fields include smooth particle hydrodynamics (SPH) method and its applications to flows in ocean engineering. He has published more than 20 papers in international academic journals such as JFM, CMAME, POF, OE, etc, with over 400 citations. He is currently undertaking several fund projects, such as the National Natural Science Foundation of China, China Postdoctoral Science Foundation. His has won several awards, such as "Youth Talent Promotion Project of Heilongjiang Province", the First Prize of Natural Science Award of the Ministry of Education, the Second Prize of Marine Engineering Science and Technology Award, and the Best Paper Award of the International SPHERIC Conference.