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Tham khảo tài liệu 'aero-acoustic test programs_3', kỹ thuật - công nghệ, cơ khí - chế tạo máy phục vụ nhu cầu học tập, nghiên cứu và làm việc hiệu quả | Simpo PDF Merge and Split Unregistered Version - http www.simpopdf.com MIL-HDBK-1X97 Figure 8 A-Jgirenter Wa33 Flow Correlation with s i Til i lcajrrt Engine lent e rl Ine Affset and Mlsaligiunent 23 Simpo PDF Merge and Split Unregistered Version - http www.simpopdf.com pumping of cooling air can be obtained with an augmenter 3 to 4 effective diameters long or about 2 3 the chosen length 3 . The relative insensitivity of pumping to augmenter length is related to the low-pumped flow pressure rise required. 24 Simpo PDF Merge and Split Unregistered Version - http www.simpopdf.com Section 7 ENCLOSURE INTERIOR FLOW CONDITIONS 7.1 Enclosure Interior Conditions. Enclosure interior conditions of interest include a interior pressure cell depression b velocity approaching aircraft engine inside of enclosure -V int c enclosure interior flow patterns hush-house test cell designs are based on providing acceptable interior conditions from the standpoint of the enclosure structure engine operation and personnel comfort and safety. Thus it is typical to limit cell depression to 2 in. 50.76 mm H 2 O interior velocity to 50 f s 15.24 m and to avoid significant recirculation of exhaust gases within the enclosure. 7.1.1 Interior Pressure. Interior pressure cell depression data are presented in Table 5 and in Figures 9 and 10. It is apparent from a comparison of Figures 9 and 10 that hush-house cell depression data group best when plotted versus the specific flow rate through the primary between the baffles net area W 1 A 1net . The Patuxent River hush-house primary exhibits a higher loss because of the inclusion of demisting elements. The N.A.S. Dallas test cell exhibits lower loss because the vaned turn from vertical to horizontal does not involve flow deceleration. Note that the cell depression varies roughly as the square of the specific flow rate or i.e. as the dynamic pressure in the minimum net area A 1net . 7.1.2 Interior Velocity. Table 5 and Figures 11 12 and 13 present .
