**5. Conclusions**

This paper designs a pneumatic hazelnut harvester for mountains areas. In the experiments, the suspension velocity of hazelnuts was obtained as 15.6 m·s−<sup>1</sup> and the critical value of the suspension velocity of leaves was 4.92 m·s−1. A coupled CFD-DEM method was used to simulate the effect of a pneumatic hazelnut harvester on the net fruit rate of hazelnuts under different combinations of operating parameters. In addition, a Box–Behnken design experiment was conducted with the sieve plate angle, the distance of the sieve plate, and the air flow velocity as factors and the net fruit rate of hazelnuts as indicators to explore the influence. The order of the factors affecting the index was air flow velocity > the sieve plate angle > distance of the sieve plate. The parameter optimization module of Design-Expert software was used to obtain the optimal combination of parameters for the factors: the sieve plate angle was 55.7◦, the air flow velocity was 14.1 m·s−1, and the distance of the sieve plate was 33.2 mm. The research results of this paper could provide a new design idea for optimizing the picking structure and sorting mechanism of the hazelnut harvester.

**Author Contributions:** Conceptualization: D.R. and H.Y.; software: H.Y. and R.Z.; validation: Y.Z. and H.Y.; supervisory role: W.W.; writing—review and editing: D.R.; investigation: J.Z.; data curation: F.L. and J.L.; funding acquisition and supervision: W.W. All authors have read and agreed to the published version of the manuscript.

**Funding:** This research was mainly supported by the Liaoning Xingliao Talent Program for Science and Technology Innovation Leaders (XLYC2002009).

**Institutional Review Board Statement:** Not applicable.

**Informed Consent Statement:** Not applicable.

**Data Availability Statement:** The datasets generated during and/or analyzed during the current study are available from the corresponding author upon reasonable request.

**Conflicts of Interest:** The authors declare no conflict of interest.
