| 摘要 |
<p>PROBLEM TO BE SOLVED: To reduce noise caused by pressure fluctuation by Karman vortex street discharged from the nozzle vane, by providing a recessed portion, a projecting portion, or a recessed and projecting portion at an arbitrary point at the front edge, the rear edge, positive pressure surface, and negative pressure surface of a nozzle vane which is radially arranged in the periphery of the exhaust turbine. SOLUTION: In this variable capacity turbo charger, a nozzle vane 3 is arranged at a nozzle portion which introduces an exhaust gas from a scroll portion of a turbine casing 1 to an exhaust turbine 2. The nozzle vane 3 is shaped like a wing, with the front and rear edges thereof being configured with a line which is perpendicular to the flow line in the wing width direction. In this case, provided are a concave portion, a projecting portion, or a recessed and projecting portion with an arbitrary shape and size at an arbitrary point at a front edge, a rear edge, a positive pressure surface, and a negative pressure surface of the nozzle vane 3. For instance, triangular recessed portions 11 are provided at the two places on the rear edge. This reduces noise caused by pressure fluctuation by Karman vortex street discharged from the rear edge of the nozzle vane 3.</p> |
