In the present work an attempt has been made to study the effect of the twisted tapes as bed internals, on the performance of the gas-solid fluidized beds. Experimental investigation has been carried out in cylindrical column with and without twisted tapes. Twelve numbers of twisted tapes of three different widths with four values of the twist ratios for each width were studied at different...

A heat exchanger network (HEN) for the process of methanol synthesis has been studied by combination of pinch design method and the application of “Twisted Tube” heat exchanger units as a new technology. The HEN is reconstructed based on the full utilization of maximum allowable pressure drops for the process hot and cold streams. An algorithm is developed to generate design procedure for twist...

in the present work an attempt has been made to study the effect of the twisted tapes as bed internals, on the performance of the gas-solid fluidized beds. experimental investigation has been carried out in cylindrical column with and without twisted tapes. twelve numbers of twisted tapes of three different widths with four values of the twist ratios for each width were studied at different sta...

in this paper, experimentally derived correlations of heat transfer and pressure drop are used in a pareto based multi-objective optimization (moo) approach to find the best possible combinations of heat transfer and pressure drop of tio2-water nanofluid flow in tubes fitted with multiple twisted tape inserts in different arrangement. in this study there are four independent design variables: t...

The article presents a practical technique for enhancing thermo-hydraulic performance of a circular tube. In this way, numerical method focusing on laminar tubular flow is used to compare the effectiveness of utilizing center-cleared twisted tapes instead of typical shape of short width tapes. Numerical analysis represented that using both center-cleared and typical shape of twisted tapes, Re e...

Optical metamaterials are usually based on planarized, complex-shaped, resonant nano-inclusions. Three-dimensional geometries may provide a wider set of functionalities, including broadband chirality to manipulate circular polarization at the nanoscale, but their fabrication becomes challenging as their dimensions get smaller. Here we introduce a new paradigm for the realization of optical meta...

We analyse the optical activity in twisted dimers, the meta-atoms of a chiral metamaterial, by introducing a simple yet accurate model for the coupling between them. The near-field interaction coefficients are derived from a Lagrangian model and include the effects of retardation, whereas the far-field radiation is based on a multipole expansion. We show that the optimum twist angle varies with...

We present an experimental and computational study of the response of twisted-cross metamaterials that provide near dispersionless optical rotation across a broad band of frequencies from 19 GHz to 37 GHz. We compare two distinct geometries: firstly, a bilayer structure comprised of arrays of metallic crosses where the crosses in the second layer are twisted about the layer normal; and secondly...