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We have developed a computer simulation code for three-dimensional viscous flow in turbomachinery based on the time-averaged compressible Navier–Stokes equations and a low-Reynolds-number k–ε turbulence model. It is described in detail in this paper. The code is used to compute the flow fields for two types of rotor (a transonic fan NASA Rotor 67 and a transonic axial compressor NASA rotor 37), and numerical results are compared to experimental data based on aerodynamic probe and laser anemometer measurements. In the case of Rotor 67, calculated and experimental results are compared under the design speed to validate the code. The calculated results show good agreement with the experimental data, such as the rotor performance map and the spanwise distribution of total pressure, total temperature, and flow angle downstream of the rotor. In the case of Rotor 37, detailed comparisons between the numerical results and the experimental data are made under the design speed condition to assess the overall quality of the numerical solution. Furthermore, comparisons under the part-speed condition are used to investigate a flow field without passage shock. The results are well predicted qualitatively. However, considerable quantitative discrepancies remain in predicting the flow near the tip. In order to assess the predictive capabilities of the developed code, computed flow structures are presented with the experimental data for each rotor and the cause of the discrepancies is discussed.

A micro-scale, high-speed compressor impeller (12mm diameter, 800,000 rpm) was tested for feasibility in regard to aerodynamic performance. The compressor was designed for application in a fist-sized gas-turbine-generator. To survive high stresses at such high temperatures, the rotor was manufactured as a single turbine/compressor/shaft unit in silicon nitride, by the Mold SDM process. Performance testing was conducted in a cold-flow rig at reduced speed of 420,000 rpm. Results from a CFD code compared favorably to measured data at this speed. Extrapolation from test conditions to full design speed was accomplished by application of CFD applied at both speeds.

Previous analyses have demonstrated that packaging of the adenovirus type 5 (Ad5) genome is dependent on at least seven cis-acting elements, called AI to AVII, which are located in the left-end region of the genome. These elements have different packaging efficiencies, and without AI through AV, viral DNA cannot be packaged. Here we report the identification of the cis-acting Ad5 packaging domain in vivo by using the Cre/loxP system. We found that an adenoviral DNA fragment (nt 192 to nt 358), which includes elements AI to AV, is excised by Cre recombinase and packaged into capsids. Furthermore, this mutant adenovirus replicated so efficiently by repetitive propagation that its purification by CsCI equilibrium gradient was possible. This study clarified that the region from nt 358 to nt 454 on the viral genome is sufficient for packaging. Recently, the helper-dependent adenoviral vector (HDAd) construction system has been developed for the purpose of gene therapy. This system uses a helper virus with two parallel loxP sites flanking the packaging signal. This region is eliminated by Cre-mediated excision, which prevents helper virus packaging. Our data provide useful information regarding factors affecting efficient elimination.

The development of high-performance turbine airfoils has been investigated under the condition of a supersonic exit Mach number. In order to obtain a new aerodynamic design concept for a high-loaded turbine rotor blade, we employed an evolutionary algorithm for numerical optimization. The target of the optimization method, which is called evolutionary strategy (ES), was the minimization of the total pressure loss and the deviation angle. The optimization process includes the representation of the airfoil geometry, the generation of the grid for a blade-to-blade computational fluid dynamics analysis, and a two-dimensional Navier-Stokes solver with a low-Re k-ε turbulence model in order to evaluate the performance. Some interesting aspects, for example, a double shock system, an early transition, and a redistribution of aerodynamic loading on blade surface, observed in the optimized airfoil, are discussed. The increased performance of the optimized blade has been confirmed by detailed experimental investigation, using conventional probes, hotfilms, and L2F system.

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Fuel film in the gasoline direct injection injector tip, or so-called nozzle tip wetting, has been found to be an important contributor of particle emissions. Attempts have been made to reduce the nozzle tip wetting by optimizing nozzle geometry designs. However, the inherent mechanism of the nozzle tip wetting formation and its link with nozzle internal flow is still unclear yet due to the lack of direct observations. To overcome this insufficiency, the nozzle internal flow and the formation process of the nozzle tip wetting were visualized in the real-scale aluminum nozzles using the X-ray phase-contrast technique. Results showed that the needle bouncing, injection pressure, and hole configuration affect the formation of the nozzle tip wetting, while the influence of needle bouncing is the most critical. A further study was conducted to examine the effect of nozzle counterbore diameter on the nozzle tip wetting. It was found that with an increase in counterbore diameter, the nozzle tip wetting slightly increased first and then decreased sharply after the counterbore diameter exceeded 0.40 mm. The mechanisms of the aforementioned phenomena were discussed in detail, which can contribute to the better understandings and control strategies of nozzle tip wetting.