EFFECT OF FLOW STRUCTURE ON HEAT TRANSFER IN COMPACT HEAT EXCHANGER BY USING FINITE THICKNESS WINGLET AT ACUTE ANGLE
Longitudinal
vortex generation is a well-known passive technique for thinning the thermal
boundary layer and hence enhancing the heat transfer, but its performance while
considering the thickness is essentially unknown. In this study, a single
triangular shaped winglet type vortex generator having finite thickness is
analyzed in a plate fin heat exchanger with triangular inserts as secondary
fins. The vortex generators are mounted on bottom and top plates of the heat
exchanger and triangular inserts forms a channel, each representing the
symmetry for the gas-side element of the compact heat exchanger. Heat transfer
and pressure drop is computed to determine the effectiveness of the vortex
generator while varying its thickness, size, and angle of attack under confined
laminar flow condition. In addition the winglet is tilted from vertical at an
angle known as acute angle and it was found to produce two longitudinal
vortices which better did the thinning of boundary layer. It is shown that
adding thickness to triangular winglet and mounting at ψ = 45°, augment heat transfer along the channel wall as high as
19.7% with a corresponding increase of 7.8% in pressure loss.
Keywords:
Longitudinal vortices, vortex generator finite thickness, triangular channel, Heat Transfer enhancement,
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- Başlangıç: 2015
- Yayıncı: YILDIZ TEKNİK ÜNİVERSİTESİ
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