Tamaki, in 11th International Conference on Turbochargers and Turbocharging, 2014 4 MECHANICAL DESIGN IMPLICATIONSĪs discussed earlier, the aerodynamic design of the tip section of a centrifugal impeller is more critical than the design of the hub section due to its higher diffusion levels. However, because of its simplicity and adaptability to any disc shape or load condition it has been widely used for all types of impeller. It is perhaps one of the important reasons for using flat shrouds, as well as making blade shapes simpler. The method using parallel sided, constant thickness “flat” shrouds or backplates can give especially accurate results and is described below. However, for general work the disc is usually divided into a number of sections having some particular shape such as conical rings, constant thickness rings, hyperbolas, etc., and then the stresses in these sections are found. For very special applications, a single equation may be used e.g., the De Laval constant strength disc. In applying the basic equations, it is necessary to express the shape of the profile by some mathematical equation or have the profile closely approximate it. The stresses are uniformly distributed over the cross section. The disc thickness varies only slightly, so the slope of the radial stresses toward the plane of symmetry is negligible. The disc is symmetrical about a plane perpendicular to the axis of rotation. These equations are based upon the following assumptions: a)
0 kommentar(er)
