Abstract: A bolt fastening structure has an upper flange and a lower flange of a casing to which inner pressure is applied, the upper flange and the lower flange defining an abutting interface therebetween; a bolt hole formed through the abutting interface; and a counterbored portion formed asymmetric about a bolt hole center. The abutting interface includes a first region extending from a bolt hole inner side edge to an upper and lower flanges inner edge and being a region where the upper flange and the lower flange are in surface-to-surface contact with each other; and a partial contact region extending from a bolt hole outer side edge to an upper and lower flanges outer edge and being a region where the upper flange and the lower flange are partially in surface-to-surface contact with each other. In the partial contact region, the upper flange and the lower flange are in surface-to-surface contact with each other in a second region, and the first region is larger than the second region.

Abstract: A casing of a turbo machine includes a casing body having an inner space; an intake nozzle which is disposed on the casing body and through which a fluid is taken into the casing body; and a straightening vane disposed in the intake nozzle and having opposite ends located in a diameter direction of the intake nozzle. Only one of the opposite ends of the straightening vane is joined to an inner surface of the intake nozzle.

Abstract: A casing of a turbo machine includes a casing body having an inner space; an intake nozzle which is disposed on the casing body and through which a fluid is taken into the casing body; and a straightening vane disposed in the intake nozzle and having opposite ends located in a diameter direction of the intake nozzle. Only one of the opposite ends of the straightening vane is joined to an inner surface of the intake nozzle.

Abstract: A bolt fastening structure has an upper flange and a lower flange of a casing to which inner pressure is applied, the upper flange and the lower flange defining an abutting interface therebetween; a bolt hole formed through the abutting interface; and a counterbored portion formed asymmetric about a bolt hole center. The abutting interface includes a first region extending from a bolt hole inner side edge to an upper and lower flanges inner edge and being a region where the upper flange and the lower flange are in surface-to-surface contact with each other; and a partial contact region extending from a bolt hole outer side edge to an upper and lower flanges outer edge and being a region where the upper flange and the lower flange are partially in surface-to-surface contact with each other. In the partial contact region, the upper flange and the lower flange are in surface-to-surface contact with each other in a second region, and the first region is larger than the second region.