# Numerical simulation of a hot-air cleaning fan for the combine harvester

## TL;DR

This paper improves crop separation in combine harvesters by simulating a hot-air cleaning fan's performance and optimizing its parameters for better efficiency.

## Contribution

The study introduces a modified hot-air cleaning fan design and identifies optimal operational parameters using Response Surface Methodology.

## Key findings

- The modified-inlet fan achieved air velocity similar to the original fan while allowing for performance optimization.
- Fan speed and inlet air temperature were identified as key factors affecting outlet air velocity and temperature.
- Optimized parameters (1445 rpm, 85°C inlet, 60°C volute) produced results consistent with theoretical predictions.

## Abstract

This study aimed to improve the separation efficiency of damp crops by developing a hot-air cleaning fan. First, the aerodynamic performance of two fans with different inlet structures was compared. The results showed a direct correlation between the static pressure and the outlet air velocity. The modified-inlet fan has an outlet average air velocity very close to the original fan of the combine harvester. Hence, the modified- inlet fan model was chosen for further analysis. Subsequent evaluations were conducted to assess the effects of fan speed, inlet air temperature, and volute temperature on fan performance. Fan speed exhibited a negative correlation with outlet air temperature but a positive correlation with outlet air velocity, at both the upper and lower outlets. Furthermore, both the inlet air temperature and the volute temperature were directly related to the air temperature at these outlets. A Response Surface Methodology (RSM) with three factors at three levels was utilized to optimize fan parameters, identifying fan speed and inlet air temperature as the predominant factors affecting outlet air velocity and temperature, respectively.The optimal set of parameters was determined to be a fan speed of 1445 rpm, an inlet temperature of 85 °C, and a volute temperature of 60 °C. Under these conditions, bench test results indicated the average air velocity and temperature are basically consistent with the theoretical optimal value.