Flux free brazing of aluminium heat exchangers

Wittebrood, A.; Bürger, A.; Kirkham, Suzanne

doi:10.1533/9780857095053.2.35

Cited by 3 publications

(1 citation statement)

References 1 publication

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“…According to Wittebrood et al [72] vehicle engines often utilize plate-type oil-coolers. The plate heat exchangers are commonly applied during vacuum manufacturing.…”

Section: Application Of the Oil-coolersmentioning

confidence: 99%

A Study on the Flow Resistance of Fluids Flowing in the Engine Oil-Cooler Chosen

et al. 2021

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Oil-coolers are necessary components in high performance diesel engines. The heat removed by the cooler is a component in the total heat rejection via the engine coolant. Oil-cooler absorbs the heat rejected during the piston cooling and engine rubbing friction power loss. During flows of both coolant and engine oil via the oil-cooler, some flow resistances occur. The aim of the study is to determine values of the flow resistance coefficient for oil going through the cooler at various temperatures. The test stand was developed to determine time needed to empty tanks from liquids flowing through oil-cooler. The flow model was elaborated to study the mentioned flow resistance coefficient with respect to changing liquid temperature. The 20 °C increase in liquid temperature resulted in a flow resistance coefficient decrease of 30% for coolant and of the much more for engine oil. It was found that better results would be achieved with flows forced by means of pumps instead of using gravitational forces on the test stand.

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“…According to Wittebrood et al [72] vehicle engines often utilize plate-type oil-coolers. The plate heat exchangers are commonly applied during vacuum manufacturing.…”

Section: Application Of the Oil-coolersmentioning

confidence: 99%

A Study on the Flow Resistance of Fluids Flowing in the Engine Oil-Cooler Chosen

et al. 2021

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Computational prediction of surface-tension flow mechanism of molten filler in a V-shaped groove geometry in the brazing process of a heat exchanger

Otsuki,

Ishimoto,

Ogasawara

et al. 2023

Int J Adv Manuf Technol

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When the temperature rises during the brazing process, only the brazing material melts because of its low melting point. Several analytical approaches have been used to describe filler flow in channels and the progression of erosion grooves. However, only a few studies have examined filler-flow behavior in microgrooves during brazing. In this study, a computational model was constructed to examine the flow in microgrooves on an extruded material’s surface. The capillary flow of the aluminum brazing material was numerically analyzed to investigate the physical properties and surface behavior. Specifically, the surface-tension flow behavior was analyzed by simulating various cross-sectional shapes of the channel grooves and various contact angles of the filler. The effects of various parameters, such as viscosity and boundary conditions, on the filler flow were also analyzed. When the cross-sectional area of the channel groove increases, the filler-flow velocity increases, and the rate of unsteady fluctuation increases with the increasing filler tip velocity. The driving force of the filler flow in the channel groove is considered to be (1) the surface tension, which is based on the filler free-surface curvature, or (2) the dynamic change in the shape of the meniscus, which can be unsteady and induced by Rayleigh–Taylor instability. As the cross-sectional area of the channel groove increases, the capillary force based on the dynamic change in meniscus shape dominates the unsteady change in filler tip velocity, rather than the surface tension based on the filler free-surface curvature formed in the groove.

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Influence of the Mg and Bi content on brazeability of MONOBRAZE material under flux-free brazing conditions

Phumprasop¹,

Yamamoto²,

Yamada³

et al. 2020

MATEC Web Conf.

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In the conventional brazing, the clad materials with the filler layer and the flux coating have been used to get good brazeability. However, an innovative Al-Si based single-layer brazing material (MONOBRAZE® material) has been developed recently which does not need filler layer by supplying molten filler from the inside of the material during brazing. In addition, a new flux-free brazing technique has also been developed. In the flux-free brazing, Mg and Bi are added to break the oxide film and to improve the wettability of molten filler, respectively. However, it is not clarified how these element works on the brazeability of MONOBRAZE® material in flux-free brazing. Therefore, in this study the effect of Mg and Bi content on the brazeability of MONOBRAZE® material was investigated. From the result, it is found that MONOBRAZE® material is applicable for flux-free brazing by adding Mg. Mg is considered to break the oxide film into fine particles and Bi is considered to assist the destruction of oxide film. From this cause, a new aluminum substrate surface was exposed which allow molten filler to move on the surface and contribute to the formation of the fillet.

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Flux free brazing of aluminium heat exchangers

Cited by 3 publications

References 1 publication

A Study on the Flow Resistance of Fluids Flowing in the Engine Oil-Cooler Chosen

A Study on the Flow Resistance of Fluids Flowing in the Engine Oil-Cooler Chosen

Computational prediction of surface-tension flow mechanism of molten filler in a V-shaped groove geometry in the brazing process of a heat exchanger

Influence of the Mg and Bi content on brazeability of MONOBRAZE material under flux-free brazing conditions

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