FRICTION REDUCING SURFACE AND A MASS AND HEAT TRANSFER ENHANCING SURFACE

摘要

The present invention relates to aerohydromechanics, power engineering, in-line processing, transport efficiency problems, to medicine and other spheres of scientific-and-technical activities and everyday engineering problems. The disclosed surface for reduction of friction with gaseous and liquid media or with their mixtures is characterized in that recesses (dimples) are made on a smooth surface with or without a protective layer, which are formed by second-order convex and concave surfaces conjugate on common tangents; in so doing, the conjugation of a dimple with initially smooth surface is accomplished using convex surfaces that form slopes, for which the initially smooth surface is tangent at points of conjugation; the concave surface, which forms the bottom part of dimple, is made smooth or with a fairing, the ratio of depth hc of dimple to dimension L1 of dimple along the direction of flow is in the range 0.001 ≤ hc/L1 ≤ 0.1, and the ratio of transverse dimension L2 of dimple to longitudinal dimension L1 of dimple is in the range 0.25 ≤ L2/L1 ≤ 1, with the surface density f of dimples being in the range 0.05 ≤ f ≤ 0.5. Dimples of the configuration described above are made on the disclosed surface for enhancement of heat and mass transfer as well; in so doing, 0.1 ≤ hc/L1 ≤ 0.5, 0.25 ≤ L2/L1 ≤ 1, and 0.1 ≤ f ≤ 0.8.