SLAG MONITORING SYSTEM FOR COMBUSTION CHAMBERS OF STEAM BOILERS

The computer based boiler performance system, presented in this paper, has been developed to provide a direct and quantitative assessment of furnace and convective surface cleanliness. Temperature, pressure and flow measurements and gas analysis data are used to perform heat transfer analysis in the boiler furnace and evaporator. Power boiler efficiency is calculated using an indirect method. The on-line calculation of the exit flue gas temperature in a combustion chamber allows for an on-line heat flow rate determination, which is transferred to the boiler evaporator. Based on the energy balance for the boiler evaporator, the superheated steam mass flow rate is calculated taking into the account water flow rate in attemperators. Comparing the calculated and the measured superheated steam mass flow rate, the effectiveness of the combustion chamber waterwalls is determined in an on-line mode. Sootblower sequencing can be optimized based on actual cleaning requirements rather than on fixed time cycles contributing to lowering of the medium usage in soot blowers and increasing of the water-wall lifetime

Solving Inverse Heat Transfer Problems When Using CFD Modeling

The chapter presents solving steady-state inverse heat transfer problems using Computational Fluid Dynamics (CFD) software. Two examples illustrate the application of the proposed method. As the first inverse problem determining the absorbed heat flux to water walls in furnaces of steam boilers is presented in detail. Three different measurement devices (flux tubes) were designed to identify steady-state boundary conditions in water wall tubes of combustion chambers. The first meter is made of a short eccentric tube in which four thermocouples on the fire side below the inner and outer tube surfaces are installed. The fifth thermocouple is situated at the rear of the tube on the housing side of the water wall tube. The second meter has two longitudinal fins that are welded to the bare eccentric tube. In the third option of the instrument, the fins are attached to the water wall tubes but not to the flux tubes as in the second version of the flux tubes. The first instrument is used to measure the heat flux to water walls made from bare tubes, while another two heat flux tubes are designated for measuring the heat flux to membrane walls. Unlike the existing devices, the flux tube is not attached to neighboring water-wall tubes. The absorbed heat flux on the outer surface and the heat transfer coefficient at the inner surface of the flux tube are determined from temperature measurements at internal points. The thermal conductivity of the flux-tube material is a function of temperature. The nonlinear inverse problem of heat conduction (IHCP) is solved using the least-squares method. Three unknown parameters are determined using the Levenberg–Marquardt method. In each iteration, the temperature distribution in the cross section of the heat flux instrument is determined using the ANSYS/CFX software

EFFECT OF THERMAL CONTACT RESISTANCE ON THE HEAT TRANSFER IN PLATE FINNED TUBE HEAT EXCHANGERS

Plate fin-and-tube heat exchangers are made by inserting oval tubes through sheet metal strips with stamped holes and then expanding the tubes slightly to cause pressure at the tube-to-strip contacts. The gap between the fin base and the outer tube surface may be filled with air or corrosion products causing a decline in the ability of plate fins to transfer heat. The contact resistance must be accounted for in the design and performance calculations of heat exchangers. In this paper, the thermal contact resistance of the fin-to-tube attachment is estimated from the condition that the dimensionless correlations for the Colburn j-factors obtained from two different methods are in good agreement. The first method is based on the experimental data, while the second one on the CFD simulation of the flow and heat transfer in the heat exchanger

The role of the victim in the plays of Florencio Sánchez

Florencio Sánchez was the first major playwright in Uruguay to treat themes relevant to his times and region. His prime concern was the portrayal of social-moral conflict in his society. His plays are divided into two main groups, those involved with rural life and those dealing with conflict in an urban setting. The urban plays expose the conflict seen in both poor and middle-class families and the rural ones expose the destruction of the family unit as old landowners are dispossessed of their land by unscrupulous speculators. This essay argues that although Sánchez’s main concern was to denounce corruption in society and to expose the victimisation of the weak, he enriches the dramatic texture of his plays by making the victims active participants. The victim is always able to articulate his or her dilemma and is given a choice of action, even if this choice is one between two evils. Frequently the survival of the family is pitched against the survival or wellbeing of the individual. Three plays have been chosen, two urban plays, En familia and La pobre gente and one rural play, Barraca abajo. The final conclusion has to be that the greed and corruption in the system are indeed destroying family unity, but that there is strength and energy found among those victimised which in some way contributes to the effect of victimisation. In the end, the choice is made by the victim

Kleist’s Puppet Theatre and the Art of Tango:Looking for the Back Door to Paradise

This edited transcript of a presentation by filmmaker/choreographer Laura Taler responds to Heinrich von Kleist’s text by taking him on as a dancing partner. It follows a simple structure of proposal and response similar to that found in the movements between leader and follower in Argentine tango. Engaging Kleist’s text in the double form of a speech and a tango performance, this critical contribution follows a twofold direction: it questions Kleist’s representation of dance as a mechanical activity deprived of any form of intelligence and it refuses his attempt to force the aesthetic experience of dance into a framework that privileges theory over bodily experience. These two classical philosophical positions are questioned and provocatively opposed to the dynamic, situated, and dialogic thought performed within a witty tango interaction

Discovering Jewish Studies Collections in Academic Libraries: A Practical Guide

The U.S. colleges and universities offering non-sectarian educational programs in Jewish Studies rely on the support of their academic libraries for research materials and library services. For college libraries which use Library of Congress Classification scheme, it is a common practice to integrate studies resources into their general library collections. Since Jewish Studies sources span a vast number of subjects within all major disciplines, shelving integration leads to the dispersion of all relevant sources and such dispersion in turn leads to a variety of problems for library professionals and library users. For collection development librarians the problems range from lack of information about collection\u27s size, strengths or weaknesses, and for library users interested in browsing the collection, dispersion of subjects creates a major roadblock. This practical guide aims at providing a solution to such problems. By identifying all relevant Library of Congress call numbers and the corresponding Library of Congress subject headings, the guide offers a simplified access to Jewish Studies sources in general library collections. It is arranged by four major discipline: Arts & Humanities, Social Sciences, Sciences, and General Works & Bibliographies. Within each discipline, specific LC call number ranges and corresponding subjects are listed. The subjects are further subdivided and precisely identified. The guide will assist collection development librarians, library liaisons, grants and fundraising professionals and especially the Jewish Studies faculty and students, in identifying and locating relevant sources

ici uniglory, 2009:Installation. Ink, paper, images & text

‘ici uniglory’ is an installation on paper. The piece intertwines fragments of six texts by Bruno Besana, Fabio Camilletti, Antke Engel, Sara Fortuna, Laura Taler, and Andrea von Kameke, written in response to the video installation UNIGLORY, a work-in-progress exhibited at ICI Berlin. The responses are edited, fragmented, and re-assembled to reflect the way the filmmaker worked with the filmed dance footage in the original installation, essentially re-choreographing words. The subtle tensions between the different responses allow for shifts and movements within the piece. The result is a poetic intermingling of voices that rub up against one another. Tension also acts as a binding agent, holding all the fragments together and allowing them to be woven into a collective text