3 results about "Diameter ratio" patented technology

The utility model relates to the field of aviation machining, in particular to an auxiliary supporting device for machining an outer circle of a part with a large length-diameter ratio. The device comprises a support, a bearing bolt, a sliding supporting assembly and a bearing. The lower end of the support is connected with a machine tool guide rail, the upper end of the support is provided with sliding grooves which are perpendicular to each other and avoid each other, the sliding supporting assemblies in sliding fit are installed in the sliding grooves respectively, the V-shaped ends of the two sliding supporting assemblies are opposite, the bearings are installed at the V-shaped ends through bearing bolts, and part of the outer circles of the bearings exceed the V-shaped ends. The two bearings abut against the outer circle of the part to be machined from the upper portion and the rear portion respectively.

The invention provides a diffusion degree-based one-dimensional key aerodynamic parameter design method for a centrifugal compressor impeller of a power generation gas turbine, which comprises the following steps of: calculating to obtain an outlet section blade tip circumferential speed, calculating a circumferential speed coefficient, giving a blade tip impeller diffusion degree, and demonstrating under an axial air inlet condition; a design scheme meeting the blade top circumferential speed of the given outlet section is obtained; for an impeller with a low load, the impeller top diffusion degree is small, scheme argumentation is completed, and key one-dimensional aerodynamic parameters of the designed rotating speed, the wheel diameter ratio and the inlet and outlet through-flow size are determined; calculating aerodynamic parameters and speed triangles of the sections of the blade top, the blade middle and the blade root under the condition of considering inlet prewhirl; for a high-load compressor impeller, under the condition that section parameters of the blade center and the blade root are not changed, the blade top diffusion degree is reduced, blade top section parameters are redesigned, recalculation of the blade top section parameters is completed, design parameters such as a blade top section speed triangle are obtained, and the method is very suitable for impeller scheme design in engineering design.

The present invention relates to a controllable pitch propeller capable of changing the pitch of the blade according to the navigation conditions of the ship, and particularly, to a controllable pitch propeller having an optimum hub to tip diameter ratio, which is capable of reducing the size of the hub in order to have a high efficiency close to the propulsive efficiency of a fixed pitch propeller (FPP). In order to achieve the above-mentioned object, the present invention relates to a controllable pitch propeller comprising a hub mounted at the propulsion shaft of the ship and a blade mounted at the circumference of the hub and having a variable pitch, and is technically characterized by an H / D ratio of the diameter (H) of the propeller to the diameter (D) of the hub of 0.170-0.2.