Andrea Luke

Computerized Tomography Application in Oil Industry Using KT-2 Signature

Oil industry situations incorporate analysis of the performance of three-phase pumps used in pumping of oil under various conditions. The very popular method of nondestructive evaluation of solid materials, X-ray tomography, has been found suitable also for such flow applications under certain restrictions. Convolution back-projection (CBP) is the most commonly used algorithm that utilizes the projection data (obtained from a CT scanner) to reconstruct the phase distributions in multiphase flows. The practical implementation of this algorithm utilizes the filter functions that are user dependent, and it incorporates the finite Fourier cutoff frequency. It leads to certain errors in reconstruction. Present study concerns with one of the inherent errors arising in CBP implementation leading to characterization of the flow cross-sections. Kanpur Theorem-2 (KT-2) utilizes different Fourier cutoff frequencies (equivalent to different numbers of data-rays) in CBP reconstructions with a fixed filter function. This KT-2 signature provides interesting information about the distribution of different phase fractions in a three-phase bubble column reactor. The variations in these signatures for different flow conditions provide the information about the flow patterns. The performance of three-phase pumps can be characterized by this technique, thus providing useful input for maintenance activities.

Special issue dedicated to Prof. Dr.-Ing. Dr.-Ing. E.h. mult. Karl Stephan on his 80th birthday

New technologies and processes demand new research in heat and mass transfer as well as the economically and ecologically efficient use of energy and natural resources cause new tasks in the fundamental understanding to heat and mass transfer. Therefore, it is not surprising that the journal Heat and Mass Transfer is of increasing interest in the scientific and technical community engaged in heat and mass transfer research and applications. The special issue is dedicated to Prof. Dr.-Ing. Dr.-Ing. E.h. mult. Karl Stephan as recognition to his lifetime work devoted to heat and mass transfer in the last decades. Due to his outstanding contributions to the international research and teaching he is extremely esteemed in the world wide community of scientists working in heat and mass transfer, thermodynamics, energy technique and of course refrigeration technique. In the last mentioned field another special issue will be published in the International Journal of Refrigeration. His former disciples, his colleagues and his friends dedicate the papers published in this special issue to him. The articles were peer reviewed for publication in Heat and Mass Transfer and reflect a spectrum of topics of his former and current interest in heat and mass transfer in a wide range. The papers include presentations on the following topics: mass diffusion, heat exchanger, mixed convection, heat transfer with phase change in pure fluids and mixtures, fouling, energy storage and multiphase flow. The first paper is unusual for Heat and Mass Transfer, but it may introduce another point of view of our daily research and its consequences. I want to express special thanks to the authors for their contributions to this special issue, and the reviewers of the manuscripts for their invaluable input, responsiveness and for making the publication of this special issue possible.