Flow quality improvement of the wind tunnel testing for a highly-loaded compressor cascade at high incidence

To obtain reliable and accurate experimental data in cascade testing, the influencing factors and the improving method of the flow quality of a highly-loaded compressor cascade under high incidence were investigated through a series of numerical simulations and experiments. The numerical method was validated by experimental data and agreed well at both incidence angles of 0° and 6°. Under the original upper end wall, both experimental and numerical results indicated an unsatisfactory flow quality of the cascade with an obvious nonuniformity of inlet Mach number, and the incidence of the central blade is 3.6° larger than the theoretical value. Using a small curved upper wall can reduce the severe flow separation on the upper wall and achieve a maximum improvement in flow quality under the critical installation angle, where the incidence deviation of the central blade was reduced to 2.1°. Using the combination of adjustable tailboards and a small curved upper end wall can further improve the cascade flow quality. Under the optimal angle of the tailboards, both the inflow uniformity and the outflow periodicity of the three middle blade passages the test requirements, and the incidence deviation of the central blade is reduced to 0.2°.

THEORETICAL AND EXPERIMENTAL JUSTIFICATION OF DISCREETLY CONTINUAL STRENG-THENING METHODS BASED ON ANALYSIS OF CONTACT INTERACTION OF MILITARY AND CIVILIAN VEHICLES ELEMENTS

The paper describes studies of breakthrough methods effectiveness for sharply increasing the resource of highly loaded military and civilian vehicles elements based on methods of their discreetly continual strengthening. These methods, unlike traditional ones, combine the advantages of discrete and continual strengthening methods and lack their main disadvantages. The analysis of contact interaction of representative structures of contacting bodies at the microlevel is carried out. They consist of fragments of contacting parts, one of which is strengthened continually, and the other part is strengthened discretely. At contact interaction at the microlevel, on the one hand, the effects of the nanоlevel are manifested, and on the other hand, the effects of the macrolevel are manifested too. Nanoeffects are the redistribution of contact forces between bodies: from smooth ones they turn into an archipelago of hilly elevations. Macroeffects are to adapt the shape of the contact parts to the distribution of contact forces, smoothing their overall unevenness. As a result, the overall effect of strengthening is achieved, increasing the strength, load capacity and resource of military and civilian vehicles elements. A breakthrough is being achieved in improving the performance of military and civilian vehicles, which corresponds to or exceeds the world level for similar products. Keywords: discrete strengthening; continual strengthening; discreetly continual strengthening; contact interaction; military and civilian vehicles