Parker Hannifin: Designing quieter heat exchangers
Parker Hannifin carefully selected the characteristics of the components of its new range of motor-driven air-oil heat exchangers. The acoustic tests showed a low noise level and confirmed that the cooling efficiency of the heat exchangers had been preserved.
Many construction and agricultural machines as well as many different types of indus-trial machines and equipment include hydraulic systems. These systems are equipped with a heat exchanger to control the oil temperature and prevent any overheating likely adversely affect their operation. No need to say that the overall perfor-mance of the hydraulic cooler is essential. However, in certain applications, this performance should not be reached to the detriment of certain noise level requirements. A heat exchanger is, by nature, a source of noise, as its function is to convey the fluid inside a matrix cooled by the air flow generated by a motor-driven fan. Parker Hannifin tackled this problem and developed, in collaboration with Cetim, a range of extre-mely quiet heat exchangers which nevertheless produce the expected cooling performance. “Cetim has broad experience in acoustics and has suitable testing equipment. Its engineers helped us to determine the characteris-tics of the most important com-ponents of the heat exchangers with regard to noise”, explains René Bibang, R&D engineer at Parker Hannifin.
Tests to validate the choices
On the basis of these recom-mendations, Parker Hannifin chose the best possible combination of important com-ponents (type of fan, quantity and shape of the fan blades, air flow, characteristics of the matrix, etc.) to reach its noise level objective. Then, in order to confirm that the calcula-ted design of the mechanical components gave the expec-ted results, Cetim carried out acoustic tests in accordance with standard ISO 3744, with ten microphones. “The tests confirmed that the new design of our heat exchangers met our expectations in terms of performance and noise, and the acoustic power level drop-ped by 2 to 3 dBA on average”, concluded René Bibang.
With its expertise in acoustics and in many branches of physics, Cetim can determine the relationship between the noise emitted by an item of equipment and the source phenomena such as shocks, friction, air flows, etc. Further to testing in accordance with the relevant procedures and analysis of the measured values, Cetim can then issue recommendations to reduce the noise.