The main shaft acts as a critical component in the driving assembly of the Model 9-26 high-pressure centrifugal fan. The rotational speed of the main shaft determines the air volume and total pressure of the fan, while the maximum combined stress of the main shaft directly affects the stable operation of the entire unit.

We are currently in an era of rapid technological iteration, where various products are being developed and applied with innovative approaches, greatly facilitating people’s daily lives. Advances in science and technology stem from deeper human understanding of natural laws, enabling people to apply established scientific principles to solve practical demands, thus spawning numerous inventions and innovations. Many of these creations are built on basic mechanical theories. In particular, a wide range of devices have been developed based on fluid mechanics principles governing gas flow. Aircraft, which greatly facilitate modern transportation, are typical products derived from fluid mechanics research, as are widely adopted Model 9-26 high-pressure centrifugal fans commonly used in summer ventilation and industrial air supply scenarios.

The existing Model 9-26 high-pressure centrifugal fan is developed on the basis of prototypes with adjustable blade installation angles. In mechanical analysis, technical optimization counts as innovative design work. Taking the Model 9-26 high-pressure centrifugal fan as the research object, this paper elaborates the calculation procedure for the combined stress of its main shaft. To solve for the maximum combined stress of the main shaft, it is necessary to clarify the source of stress, namely the loads acting on the shaft material, which puts forward specific requirements for the structural design and mechanical strength of the fan shaft components.

The combined stress of the main shaft can be calculated from its maximum bending moment and torque. The shaft torque can be calculated via the standard formula: T=9549⋅P/n (where P stands for output power, n represents rotational speed). The maximum combined stress σ of the main shaft is derived by extracting the square root of the sum of the square of the maximum bending moment and the square of the torque, with an equivalent coefficient of 0.5 assigned for the impeller configuration. Required calculation results can be obtained following the above calculation steps.

The calculated maximum combined stress serves as a core design benchmark for manufacturing Model 9-26 high-pressure centrifugal fans. It helps manufacturers control production quality and enables customers to grasp the operating state of the fan, so that the equipment can run at its designed efficiency to the fullest extent.