Limited by the poor transient response performance of turbochargers, the dynamic performance of aviation piston engines tends to deteriorate. In a bid to enhance the turbocharger's acceleration capabilities, this study scrutinizes various factors impacting its performance. Based on the operational principles and transient response process of the turbocharger, three types of inertia—namely, aerodynamic inertia (ADI), thermal inertia (TI), and mechanical inertia (MI) — are identified and addressed for design. To begin, this paper pioneers the innovative definition of a method for evaluating the transient response performance of the turbocharger. This method incorporates the introduction of an ADI parameter, inspired by the definition of MI. Subsequently, a thin-walled volute design with a low Biot number and a lightweight turbine impeller is introduced to reduce the turbocharger's TI and MI. The simulation results of the flow field distribution within the volute and diffuser demonstrate the comprehensive design method's effectiveness in improving gas pressure and temperature distributions in these components. Notably, the pressure distribution fluctuation in the constant moment-of-momentum volute (CMV) is 62.8% lower than that in the constant velocity moment volute (CVMV). The low-TI thin-walled volute not only enhances the turbocharger's response speed but also reduces its weight by approximately 40%. The impact of three types of inertia on the engine's response speed is quantified as follows: ADI (94%) > MI (5%) > TI (1%). This conclusion has been verified through test results of both the turbocharger and the engine. This design method not only significantly improves the turbocharger's response performance but also offers valuable insights for the optimal design of other blade mechanical systems.
Based on the demands of compact heat exchangers and micro cooling channels applied for aviation thermal protection on aero-engines, the elbow local flow resistance characteristics for supercritical pressure aviation fuel RP-3 flowing in adiabatic horizontal serpentine tubes with the inner diameter of 1.8 mm and the mass flux of 1179 kg/(m2·s) were experimentally studied. The long-short-tube method was used to obtain the elbow pressure drop from the total serpentine tube pressure drop, and the effects of system pressures (P/Pc = 1.72–2.58) and geometry parameters including bend numbers (n = 5–11), bend diameters (D/d = 16.7–27.8), and bend distances (L/d = 20–60) on elbow pressure drops and local resistance coefficients are analyzed on the basis of the thermal physical property variation. The results show that both the increase in the elbow pressure drop and the decrease in the local resistance coefficient with temperatures speed up at the near pseudo-critical temperature region of T > 0.85Tpc. And the growth of the elbow local pressure drop could be inhibited by the increase of system pressures, while the local resistance coefficient is slightly affected by pressures. The influence of bend diameters on the local resistance coefficient is mild when D/d is larger than 22.2 in the premise of fully developed flow in straight tubes. Furthermore, a piecewise empirical correlation considering the bend diameter and physical property ratio is developed to predict the elbow pressure drop of the serpentine tube and optimize the layout of the cooling tube system on aero-engines.