02787nas a2200265   4500008004100000022001400041245012200055210006900177260010600246300001400352490000700366520179500373653002202168653001802190653003002208653001102238653002002249653001502269653002202284100002502306700002702331700001602358700002102374856012602395       2008                        eng d  a0009-250900aIdentification and characterization of flow structures in chemical process equipment using multiresolution techniques0 aIdentification and characterization of flow structures in chemic  aTHE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLANDbPERGAMON-ELSEVIER SCIENCE LTDcNOV  a5330-53460 v633 a<p>Planar information of velocity from 2D particle image velocimetry (PIV) and large eddy simulation (LES) data have been studied using multiresolution wavelet transform (WT) formalisms, i.e., discrete and continuous WT. Identification of dominant energy containing structures with their characterization in terms of fractal spectra have been carried out for industrially important equipment exhibiting turbulent behavior. These include annular centrifugal contactor, jet loop reactor, ultrasound reactor, channel flow, stirred tank and bubble column reactor. The characterization of their dynamics based on denoising the data and studying the local energy along the WT scales show sensitive variation and this helps in identifying the size and shape of structures. A dependency is seen between mixing time and the higher order moments of length scale distribution, viz., skewness and kurtosis and a generalized correlation has been built up for important types of equipment and associated flow parameters. The correlation is not only based on the knowledge of reactor geometry and operating conditions but also on the flow structures via their statistical parameters. Wavelet transform modulus maxima (WTMM) methodology has been used to study the evolution of structures and their interaction in a reduced dimensionality by evaluating the fractal spectra. Classification studies have been carried out using principal component analysis (PCA) of the fractal spectra. The results obtained show clear classes for the six types of equipments and delineate regimes to obtain benchmark patterns of flow hydrodynamics based on PCA co-ordinates. This methodology offers a generalized way for the optimal design and operation of different types of reactors. (c) 2008 Published by Elsevier Ltd .</p>10aChemical reactors10ahydrodynamics10aLength scale distribution10amixing10aModel reduction10aTurbulence10aWavelet transform1 aDeshpande, Sagar, S.1 aJoshi, Jyeshtharaj, B.1 aKumar, Ravi1 aKulkarni, B., D.  uhttps://library.ncl.res.in/content/identification-and-characterization-flow-structures-chemical-process-equipment-using-002089nas a2200193   4500008004100000022001400041245008500055210006900140260007100209300001400280490000700294520135300301100002501654700003601679700002401715700002701739700001601766856011301782       2009                        eng d  a0888-588500aEffect of flow structures on heat transfer in single and multiphase jet reactors0 aEffect of flow structures on heat transfer in single and multiph  a1155 16TH ST, NW, WASHINGTON, DC 20036 USAbAMER CHEMICAL SOCcNOV  a9428-94400 v483 a<p>High frequency experimental measurements by hot film anemometry (HFA) of liquid velocities and temperature in the region of vapor-liquid (VL) and solid-liquid (SL) interfaces for two important reactor types, namely, condensation jet and jet loop reactors, have been studied for their heat transfer characteristics. An algorithm for flow structure identification has been devised from velocity data based oil (i) zero crossings and (ii) continuous wavelet transform. The wavelet transform algorithm is especially found to be useful in accurately estimating both the age and size distributions of eddies near interfaces in a multiscale framework Using these distributions, it is shown that the calculated values of heat transfer coefficients (HTC) at the SL and VL interfaces show remarkable correspondence with the HTC values obtained experimentally from instantaneous temperature measurements. For this purpose, a modified capacitance model has been proposed that takes into account the information about both the age and size distributions. The results obtained by the present methodology show the improvement possible for calculating the HTC at interfaces when compared with the earlier surface renewal models. It may therefore be used to study the interaction between flow dynamics and heat transfer behavior in chemical process equipment</p>1 aDeshpande, Sagar, S.1 aMathpati, Channamallikarjun, S.1 aGulawani, Sagar, S.1 aJoshi, Jyeshtharaj, B.1 aKumar, Ravi  uhttps://library.ncl.res.in/content/effect-flow-structures-heat-transfer-single-and-multiphase-jet-reactors-0