Improvements in the Aerodynamic Design of Explosion-Proof Centrifugal Fans

Improvements in the Aerodynamic Design of Explosion-Proof Centrifugal Fans

Under design conditions, explosion-proof centrifugal fans exhibit minimal vortex shedding and feature a complex internal structure. Their flow efficiency is also very high, allowing fan performance to be easily predicted using standard software and numerical calculation methods. However, under non-design conditions, there is significant vortex formation, flow separation, and low flow efficiency, making it difficult to accurately simulate the performance of explosion-proof centrifugal fans through numerical modeling. Furthermore, due to limitations in CFD software and computational technology, the flow field calculations for the entire mechanical assembly described here can only achieve numerical simulations that combine the impeller and housing geometries; they cannot perform calculations for the entire mechanical assembly. The true objective is to calculate the three-dimensional flow field—specifically, the combination of the impeller, vortices, inlet, and connecting ducts. By utilizing aerodynamic design software and design experience with explosion-proof centrifugal fans, the aerodynamic design is improved through an engineering approach. By selecting several empirical coefficients, an aerodynamic design diagram for a high-performance fan is provided. Subsequently, CFD software is used to calculate the three-dimensional turbulent flow field within the fan, yielding the total pressure and efficiency for the specified flow rate. Since fan performance can be estimated during the design phase, if the engineering design method fails to meet expected performance, new explosion-proof centrifugal fans are developed by adjusting empirical design parameters, engineering design, and the three-dimensional flow field to modify aerodynamic testing and computational results. Performance is predicted, followed by prototype testing to verify the predicted performance until requirements are met. If unsatisfactory, a new explosion-proof centrifugal fan design is created, performance is estimated through calculations, and prototype testing is conducted until the estimated performance from the engineering design and the measured performance of the prototype are sufficiently close to the desired specifications, at which point the design is finalized. This entire process is known as the modern design method for explosion-proof centrifugal fans.