Derivative Design of Axial Fan Range: From Academia to Industry

Abstract

The work presented in this paper concerns a useful method for axial fans preliminary design based on the “Derivative Design” concept. The emphasis is, on one side, on education and, on the other, on the practical help that such method can provide in the early preliminary design process. A complete data set of an axial fan measured with ISO 5801 standards is the start point for the investigation and the prediction of the multiple possible performance that different fan configurations can provide, in terms of dimensionless duty coefficients. In particular, configurations with different number of blades, and hence of solidity, are studied. The typical options of derivative design are explored and relations for performance prediction are presented. A detailed description of the derivative design methodology is followed by tests and validation. The tools employed are a fully three dimensional code, the Advanceded Actuator Disk Mode (AADM), and two other in-house codes, the Meanline Axisymmetric Calculation (MAC) and Axisymmetric Laboratory (AXLAB). Results of the derivative design method are reported, showing a good accuracy against the AADM data. The MAC and AXLAB ensure still acceptable results when increasing the solidity of the machine. On the contrary, a decrease of solidity leads to higher relative errors in the prediction of the load coefficient. In conclusion, an exploration of the possible fields of operation of a blade profile can be carried out by a correct prediction of the stage diffusion factor.

Exploration of Axial Fan Design Space with Data-Driven Approach

“…In reality, a larger set of parameters concur to the performance, such as blade aspect ratio, chord and twist distributions along the blade span, hub-to-tip ratio, solidity, blade number, and tip gap [6], related to the three-dimensional design criterion or even to the manufacturing process of the fan. All those parameters need to be selected during the design process, and often this is done by exploiting other charts, which were also derived from consolidated empirical manufacturer experiences [7]. In these charts, correlations between some of the design parameters are presented and summarized into different coefficients and correction factors that can enrich the classic design space given by Euler work analysis.…”