Wavy air fins are used in the construction of aluminum compact heat exchangers which are used in thermal equipment for agriculture, construction, and industrial applications. Since atmospheric air convective heat transfer coefficient is among the lowest of all fluids, there is a special interest in the optimizing of the geometry for this type of heat exchangers. One of the biggest challenges in designing cooling solutions for agriculture applications is the clogging effect on the performances of the heat exchangers. Clogging leads to a critical performance reduction of the compact heat exchanger used for these types of applications. This specific study, which was conducted in RAAL S.A company in collaboration with the University “Politehnica” of Timisoara”, checks the influence of the wavy air fin amplitude on the thermal and hydraulic performances and tries to find an optimum solution suitable for these specific projects. So, starting from the standard existing amplitude, different amplitude values were studied analytically. The analytical studies were further confirmed by real life measurements. The scope of the study was to find an optimal value for the amplitude that can further improve the overall performance of the aluminum compact heat exchangers and reduce the clogging effect.

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The air cooled heat exchangers are used on a wide range of automotive, construction, industrial or agriculture applications. As the atmospheric air has the lowest convective heat transfer coefficient it is necessary to use different extended surfaces with different geometries. The need for this type of heat exchanger and the relative limited information in the literature, conducted to a study, done at RAAL S.A. Company in collaboration with University “Politehnica” of Timișoara that focuses on finding the optimum length of the straight section depending on the cooler thickness and wavy fin pitch. In the first step we performed analytical investigations on a multiple number of core thickness dimensions, for 5 mm fin pitch. The optimum length of this straight section is considered the section for which the fins that have the highest area goodness factor (J/f). The above numerical study then was to be confirmed in the second step by real life testing. The scope of this study was to determine a relation that shows the influence of the straight fin section on the thermal and hydraulic performances.

In the past few decades heat exchangers, especially air cooled ones, have become very important equipment in different fields of industry. This led to an active research in finding ways to reduce their overall size and costs. A very important role played in reducing the size of the heat exchanger is the convection capability of air, by being the lowest one, dictates the overall size of the heat exchanger. For this reason we are forced to use extended heat transfer surfaces on the air size. The geometry of such extended surfaces has a high impact on heat and pressure drop performances. The present paper focuses on a study, conducted at RAAL S.A. with the support of University “Politehnica” of Timișoara, to find the influence of the corrugation amplitude of a special kind of extended surface named wavy fin, in the overall performances of a heat exchangers by means of area goodness factor (j/f). Designing and building the different geometries needed in the study will be overkill for the company so we have decided to conduct this study with the help of CFD simulations. In order for this to work we will validate the numerical model with the help of a single experimental test, reducing the time and cost of the entire study. These results are afterwards used to modify the fin’s design to obtain an optimum one.