# Characterisation of the Pump-Suction Flow Field of Antarctic Krill and Key Influencing Factors
## 4 Conclusions  
Based on the above numerical simulation analysis and calculation, the following conclusions can be obtained:  
1. The simulation study demonstrated that when the centrifuge rotation speed was within the range of 550-600 rev/min, the collision between the krill body and the pumping machine wall, as well as the krill body itself, was significantly reduced. This result indicated that this condition resulted in the lowest damage rate. Within this specific range of rotation speeds, the growth rate of the velocity gradient in the centrifugal region exhibits a minimum at each working condition, particularly at 550 rev/min. Additionally, the increase in the particle collision force on the krill body with an increasing rotation speed is marginal, suggesting that this range can effectively balance centrifugal separation efficiency and mechanical damage control.
2. The mixing ratio of krill-water is 4:6, and the centrifuge flow characteristics and krill density are selected to reach the optimal match. This process ensures that the krill body is minimised by the particle collision force and internal extrusion pressure. In this scenario, the propulsion exerted by the water flow on the krill body is found to be less significant than in the 3/7 condition. This, in turn, results in a decrease in the frequency of collisions between the krill body and the inner wall surface of the pumping apparatus. Moreover, in contrast to the 5/5 condition, the decline in krill body density serves to reduce extrusion stress between the groups, thereby conferring a dual benefit in the form of damage inhibition.
3. Through the combined analysis of the interaction effect of rotational speed and mixing ratio, it was determined that a combination of 550-600 rev/min and a 4/6 mixing ratio could optimise the velocity distribution of the flow field and the mechanical response of the krill body concurrently. In this condition, the maximum velocity in the centrifuge and the particle collision force on the krill body were both significantly reduced, and the uniformity of the distribution of the particle collision force was improved. In addition, the damage to the krill body was significantly reduced in comparison with the other 25 groups of conditions. This provides a basis for the selection of krill suction pump parameters.  
**Author Contributions:** Conceptualization, Writing--Original Draft, Data Curation, Formal Analysis, P.L.; Investigation, Resources, Software, Writing--Review and Editing, Validation, L.L.; Visualisation, Supervision, Funding Acquisition, Z.X. All authors have read and agreed to the published version of the manuscript.  
**Funding:** This research was supported by the National Key R&D Program of China (2023 YFD2401203).  
**Institutional Review Board Statement:** Not applicable.  
**Informed Consent Statement:** Not applicable.  
**Data Availability Statement:** This research data has been presented in current paper.  
**Acknowledgments:** All authors would like to express the sincere thanks to editor and reviewers for valuable comments.  
**Conflicts of Interest:** The authors declare no conflicts of interest.