This forms a mixture of the pre-ceramic polymer and interface materialcoated reinforcing fibres. moulding an exhaust manifold-shaped structure from the mixture by placing the mixture on at least a portion of the castahle material, and firing the structure. The manifolds produced are resistant to ero
A comparative study of elliptical and circular sections in one- and two-row tubes and plate fin heat exchangers
โ Scribed by L.A.O. Rocha; F.E.M. Saboya; J.V.C. Vargas
- Publisher
- Elsevier Science
- Year
- 1997
- Tongue
- English
- Weight
- 524 KB
- Volume
- 18
- Category
- Article
- ISSN
- 0142-727X
No coin nor oath required. For personal study only.
โฆ Synopsis
In this work, a two-dimensional (2-D) heat transfer analysis is performed in one-and two-row tubes and plate fin heat exchangers (circular and elliptical sections), using experimentally determined heat transfer coefficients from a heat and mass transfer analogy. The temperature distribution on the fin and air free stream, and the fin efficiency are determined for heat exchangers, with eccentricity 0.5 and 0.65, as a function of the Reynolds number. For tubes and plate fin heat exchangers, new numerical results of fin efficiency for elliptical tubes are compared with published results for circular tubes. A relative fin efficiency gain of up to 18% is observed in the elliptical arrangement, as compared to the circular one. The efficiency gain, combined with the relative pressure drop reduction of up to 25% observed in previous studies show the elliptical arrangement has the potential for a considerably better overall performance than the conventional circular arrangement.
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