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Yacht engine cooling,All engines generate heat, especially marine engines.In marine applications, exhaust lines must be cooled to control heat transfer to the hull and other ship components. This goal is achieved by utilizing seawater as a heat transfer medium.


Our client is a manufacturer of exhaust pipes and cooling systems for yacht engines. He needed to redesign the machine’s exhaust pipe cooling system.
The cooling system owned by the customer was not performing well, the cooling water could not mix effectively with the exhaust gases and kept clinging to the outer walls. The result is that the exhaust gas temperature is too high, and the temperature of the exhaust pipe wall is also very high, which damages the paint and resin of the yacht’s hull.
HAPOO’s technical department decided to tackle this problem with Computational Fluid Dynamics (CFD). We analyzed the existing cooling system to understand key issues and designed a new system.

Thermal photos show temperatures exceeding 130°C at some points in the exhaust system.

Underperforming cooling system

At this stage, we performed a CFD simulation of the existing cooling system to understand its strengths and weaknesses.
The results show that the water flow has unique properties due to the tangential injection in the cylindrical mixer: it enters the mixer, expands on the wall, maintains this expansion motion along the outlet line of the exhaust pipe to the position of the transformation axis, and remains attached to the wall. As the water remains “centrifugal” on the outer walls, the “hot air core” follows the current line.

The result of all these factors is an exhaust box wall temperature in excess of 130°C


HAPOO’s technical department has developed a system for cooling the exhaust system of an engine. A header with three AL full-cone nozzles is placed above the exhaust pipe. Nozzles inject additional water from the main circuit.
Gas cooling system before our intervention
Part of a yacht engine exhaust pipe. The gas flow stays hot in the center as the cooling water stays on the walls

The system developed by HAPOO effectively reduces the temperature of the exhaust gas and the wall of the exhaust pipe.
Before our intervention, the exhaust gas and exhaust box were at temperatures of 155°C and 105°C respectively. With our cooling system, the temperature is reduced to 95°C and 65°C. The cooling system has been improved by 38%.


full cone nozzle

The AL Solid Cone Nozzle offers several advantages due to its unique construction, which incorporates S-shaped vanes inside. They provide maximum free passage in a full cone nozzle and can easily handle impurities or circulating liquids.

Welcome to our product page for more details.

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