No abstract

This paper presents some development of the turbocharger turbine unsteady measurement under pulsating conditions. On the basis of the indirect turbine power measuring principle by using a radial compressor to load turbine, a new turbine test rig is set up, which uses an “auxiliary” turbocharger instead of the intercooler to achieve a close‐cycle loading. The experimental results show that it can enlarge the load range and achieve a benefit of compactness. Some key instantaneous data measurements including speed and inlet temperature are discussed and a new method of phase shift is introduced. Using the newly developed test rig, an automotive turbocharger turbine is measured under two pulse frequencies of 40 and 60 Hz. The instantaneous mass flow and efficiency maps are obtained with the instantaneous data measurement, and the obvious hysteresis surrounding the steady curve was also found.

Under the premise of the theory of surface elasticity, the scattering of plane compressional waves (P-waves) in the surface of a semicylindrical core-shell structure within the nanoscale elastic confinement half-space is studied by using the method of eigen-function expansion. The generalized Y-L equation is used to give the nanoscale boundary conditions, and the dynamic stress concentration factor (DSCF) along the interface of core-shell structure induced by the plane elastic wave are derived and numerically evaluated. Under different incident wave frequencies, surface energy, and shear modulus, when the radius of the core-shell structure is reduced to the nanometer level, their influence on the DSCF is very significant. These have been confirmed by numerical calculations.