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1

The Effect of Regulating Elements on Convective Heat Transfer along Shaped Heat Exchange Surfaces

100%

Cernecky J., Koniar J., Brodnianska Z.

Chemical and Process Engineering

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2013

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issue 1

2

Diffraction microtomography with sample rotation: influence of a missing apple core in the recorded frequency space

100%

Vertu S., Delaunay J.-J., Yamada I., Haeberlé O.

Open Physics

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2009

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vol. 7

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issue 1

22-31

EN

Diffraction microtomography in coherent light is foreseen as a promising technique to image transparent living samples in three dimensions without staining. Contrary to conventional microscopy with incoherent light, which gives morphological information only, diffraction microtomography makes it possible to obtain the complex optical refractive index of the observed sample by mapping a three-dimensional support in the spatial frequency domain. The technique can be implemented in two configurations, namely, by varying the sample illumination with a fixed sample or by rotating the sample using a fixed illumination. In the literature, only the former method was described in detail. In this report, we precisely derive the three-dimensional frequency support that can be mapped by the sample rotation configuration. We found that, within the first-order Born approximation, the volume of the frequency domain that can be mapped exhibits a missing part, the shape of which resembles that of an apple core. The projection of the diffracted waves in the frequency space onto the set of sphere caps covered by the sample rotation does not allow for a complete mapping of the frequency along the axis of rotation due to the finite radius of the sphere caps. We present simulations of the effects of this missing information on the reconstruction of ideal objects.

3

The Effect of Regulating Elements on Convective Heat Transfer along Shaped Heat Exchange Surfaces

100%

Cernecky J., Koniar J., Brodnianska Z.

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vol. 34

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issue 1

5-16

EN

The paper deals with a study of the effect of regulating elements on local values of heat transfer coefficients along shaped heat exchange surfaces with forced air convection. The use of combined methods of heat transfer intensification, i.e. a combination of regulating elements with appropriately shaped heat exchange areas seems to be highly effective. The study focused on the analysis of local values of heat transfer coefficients in indicated cuts, in distances expressed as a ratio x/s for 0; 0.33; 0.66 and 1. As can be seen from our findings, in given conditions the regulating elements can increase the values of local heat transfer coefficients along shaped heat exchange surfaces. An optical method of holographic interferometry was used for the experimental research into temperature fields in the vicinity of heat exchange surfaces. The obtained values correspond very well with those of local heat transfer coefficients αx, recorded in a CFD simulation.

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2 Chemical and Process Engineering

1 Open Physics

2 2013

1 2009

2 Brodnianska Z.

2 Cernecky J.

2 Koniar J.

1 Delaunay J.-J.

1 Haeberlé O.

1 Vertu S.

1 Yamada I.

The Effect of Regulating Elements on Convective Heat Transfer along Shaped Heat Exchange Surfaces

Diffraction microtomography with sample rotation: influence of a missing apple core in the recorded frequency space

The Effect of Regulating Elements on Convective Heat Transfer along Shaped Heat Exchange Surfaces