Experimental and numerical investigation of a reversible fan performance

In engines used in construction and agricultural machinery operating in polluted environments, the radiator can quickly clog, which can lead to the engine cooling system failing to perform its intended function. In recent years, bidirectional fans have been used as a solution to this problem. The processes of the thesis, which aims to determine optimal design criteria for the application of a twoway radiator cooling fan in internal combustion engines, can be summarized under four main headings: Design, manufacture, and experimental measurement of the performance of a two-way radiator fan; Testing the reliability of the simulation processes calculated using CFD simulations for the performance of the designed and manufactured two-way fan through experimental measurements; Investigating its performance at different casing diameters, blade angles, and speeds using CFD simulations; Determining the performance of a reference fan selected from the fan designs whose performance was calculated using CFD simulations under normal operating and reverse-flow conditions. In the first stage, a reference two-way fan was designed and manufactured. In the second stage, the performance of the designed and manufactured fan was measured experimentally. In the following stage, six flow areas were designed for two casing diameters and three blade inclination angles. For each flow area, fan performance was investigated at three different speeds. In the final stage, two flow field designs were created, one under normal fan operating conditions and the other under 180° reverse rotation of the fan blades, taking into account the fan geometry that performed best in the previous section. Seven CFD simulations were conducted: 3 fan speeds for normal operating conditions and 4 fan speeds for 180° reverse rotation of the fan blades. In the CFD simulations conducted for the designed and manufactured fan, the deviation from the experimental measurement data at maximum operating point was below 3%, while the deviation remained below 5% across all operating curves. The simulations determined that the optimal design in terms of performance was the 32° blade pitch angle design. From the calculations made under reverse flow operating conditions where the fan blades are rotated 180°, it has been observed that the fan can provide the air flow required for cleaning from the radiator at speeds above 2000 rpm.