Heat Exchanger Services

Heat Exchanger Services Vancouver

Heat Exchangers in an Aircraft

There are various applications of Heat Exchangers. The core purpose is to aid in cooling is extensively used in aviation sector besides in refrigerators, car air conditioning etc. To save the consumption of fuel and for efficient cooling, one needs to keep the heat exchangers clean for smooth functioning.

A heat exchanger is a piece of a machine built for resourceful heat transfer from one medium to another. The two most commonly use heat exchanged in aviation are the flat tube and the plate-fin heat exchangers.

For a commercial aircraft carrying passengers on board, it is pre-requisite to have a pleasant cabin environment for a comfortable journey. This is where the heat exchangers located in the area at the transition between fuselage and wings come into play making the cooling possible. Heat exchangers enable thermal energy to be transferred from one medium to another without the two media that is water and gas coming into contact with each other.Heat Exchangers sevices
Application of Heat Exchanger
Heat exchangers are commonly used to cool hydraulics, RAM air, auxiliary power units, gearboxes, and many other components that consist of an aircraft. Although temperature is a feature associated with liquid cooling, when heat exchanger services are used at high altitudes air density and pressure are additional features considered. For sufficient airflow, heat exchanger’s fan must be carefully selected based on the ambient pressure. At high altitudes, the density of air is drastically lower. So it takes more airflow to remove the same amount of heat since the same volume of air has fewer air molecules for absorption of heat.

The Role of Heat Exchanger in an Aircraft
For relatively large aircraft and for efficient cooling at high altitudes heat exchanger installation is an essential part of the aircraft’s aerodynamic design. Integrated wing-airfoil/heat-exchanger installations appear to be attractive options.

Liquid cooling can provide notably better performance than air cooling alone that too quieter than air cooling and can be not vulnerable to altitude. System’s performance can be optimized by moving from air cooling to liquid cooling. They also reduce weight and power consumption by abolishing the need for large fans or the need for wide spacing for placing components.  Heat exchangers, Liquid-cooled chassis  and cold plates are employed to provide thermal solutions for the purpose of cooling aircraft fluids and electronic equipments that are installed.

Though the addition of water vapor reduces the density of air, as does higher temperatures, the impact of humidity on density is less than the impact of high altitudes. Also, air is significantly colder than at sea level on high altitudes.

Why Plate-fin and flat tube heat exchangers?
They are engineered for high performance with poor heat transfers fluids such as oils and ethylene glycol solutions for efficient cooling. Aluminum plate-fin heat exchangers are made of finned passages that are separated by flat plates and have a unique internal pattern to maximize heat transfer. They offer the best performance to-weight ratio and can be applied for air-to-air, air-to-liquid or liquid-to-liquid cooling. Aluminum flat tube heat exchangers are made up of several flat tubes that come with multiple extended surface outlets within each tube. Here, the fins are typically vacuum-brazed between each flat tube and it is known to form a passage for the second fluid. These flat tubes are a lower cost alternative to plate-fin designs. Both these type of heat exchangers are vacuum-based for ‘rugged-ization’.

Process of Heat Exchanger Service
In the lamella heat exchanger used in a commercial aircraft the two medium used are the air heated up by the engines and the cold ambient air from outside. The two airflows flowing in separate circuits through vertical and parallel aluminum plates constitute the central part of the heat exchanger. By mixing adequate proportions of these airflows it is possible to control the temperature of the cabin air and to increase or decrease it to the desired level.

Cleaning Process
To keep free the aluminum plates inside the heat exchangers, from deposits and dirt built up during flying operations, they need to be cleaned at regular intervals. It is difficult because the housing and the core cannot be separated and assembled again as the plates are sensitive plates to access. It is possible to establish the accumulation of dirt on the basis of past experiences with regards to the build-up. It can also be calculated on the basis of the number of aircraft flying hours. Due to the rigorous safety requirements regarding any possible deposit and the high standard of cleanliness demanded, the heat exchangers have to be cleaned to high standards. This is vital because substandard cleaning could result in a loss of pressure in the heat exchanger, which is unacceptable.

Earlier airline companies needed to hire engineers that would conduct elaborate investigations into the dirt accumulation and physical/chemical surface analysis of the aluminum plates in the center. Now, there are agents for heat exchanger services that can help you out by scanning electron microscope to spot the different elements of the mount up dirt.



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