Optimization of Inlet Channel to Water Filter for Fish Farming

Abstract

This master thesis was performed in collaboration with NP Innovation. The purpose of this project was to develop a new inlet channel and two adapters for a water filter used in fish farming. Two different sizes of filters are included in the company's product portfolio. For both filters there is one inlet channel each in a corresponding size. One inlet channel consist of an adapter welded to the filter and a channel mounted on the adapter. It was established that it would be beneficial for the company if one universal channel was used instead, with the adapters made to fit different sizes of the filter. This would result in decreased production costs for the company.

The project was structured according to Ulrich & Eppinger Design Methodology. It contained planning, benchmarking, concept development and Design for Manufacturing. The project stops before production ramp-up. The concept development phase included generating ideas in CAD, and then testing them with CFD analysis. The CFD analysis was made to compare the concepts with each other, with the current inlet channel, and against the product specifications. The final concept was chosen through the concept selection phase that included concept screening, concept combination and concept scoring.

Initial simulations were made on the company's current solutions to set a benchmark for the final concept. One of the company's solutions showed severe recirculation and dead zones while another already gave an acceptable flow. During the concept development phase, it was discovered that the edge of the inlet channel causes the main separation of the flow in the inlet channel.

The deliverable to the company is a CAD model of a final concept. The final concept includes a rounded wall guiding the water into the inlet channel. The solution decreases recirculation and distributes the flow throughout the entire channel, while maintaining an acceptable velocity for the water. The manufacturing has slightly worsened in the complexity of the channel, but improvements were made in relation to only having one channel instead of two.

While solving the problem in this master thesis, it also brings further development and opportunities for the health and safety of fishes in fish-farms.

Popular Abstract

Inefficient flow slows down the cleaning of water to fish farms, leading to unhealthy fish and low yield. Our newly designed inlet channel optimizes the water flow by removing flow separation, reducing the pressure loss and maintaining a uniform velocity throughout the channel.

With a growing population and increased demand for sustainable protein-based food, the fish farming industry is expected to expand. Water at fish farms is cleaned mechanically by a filter that can be two meters in diameter and four meters in length. A large volume flow is approaching the filter and an optimized path into the filter is essential. Should the water enter the filter with too much turbulence or with the wrong velocity, it could lead to the water not being cleaned at a rate necessary for the fish to survive. This project was performed in collaboration with a water cleaning company specialised in aquaculture, NP Innovation. The company currently has different sizes of channels for different sizes of filters. This project aims to develop a new universal inlet channel, with two different adapters made to fit two different sizes of filter. Furthermore, the goal is to guide the water more effectively into the channel than our analysed starting point.

It started with CFD analysis of the company’s two current solutions for guiding the water into the filter, the inlet channel and the wing walls. The inlet channel consists of an adapter welded to the filter and a channel mounted onto the adapter. The wing walls are two walls guiding the water into the filter. From our analysis, it was clear that the wing walls contributed to tremendous recirculation and dead zones in front of the filter inlet. The current inlet channel did not cause as violent recirculation as the wing walls but still had space for improvements. Especially the separation of the water entering the inlet channel was a major area that could be improved.

The concept development phase included generating ideas in CAD, and then testing them with CFD analysis. The CFD analysis was a great tool to compare the concepts with each other, against the current inlet channel, and against the product specifications. The final concept was chosen through the concept selection phase that included concept screening, concept combination and concept scoring.

Delivered to the company is the final concept in a CAD-model. The solution decreases recirculation while maintaining an acceptable velocity for the fluid. The key geometry in our concept is a rounded inlet at the beginning of the channel, keeping the water from separating with the channel wall. The manufacturing has slightly worsened in the complexity of each channel. However, improvements were made in relation to only having one universal channel for all sizes of filters, instead of one channel for each size. While solving the problem in this master thesis, it also brings further development and opportunities for the health and safety of fish in fish-farms.

• author: Cassé, Mimmi and Vester Stephensen, Oliver
• supervisor: Per Kristav
• organization: Innovation
• course: MMKM10 20261
• year: 2026
• type: H2 - Master's Degree (Two Years)
• subject: Technology and Engineering
• keywords: Fish Farm, Water Filter, Inlet Channel, CFD-analysis, CAD, Flow Optimization
• language: English
• id: 9242501
• date added to LUP: 2026-06-24 06:41:36
• date last changed: 2026-06-24 06:41:36