Incompressible lifting-surface aerodynamics for a rotor-stator combination

Current literature on the three dimensional flow through compressor cascades deals with a row of rotor blades in isolation. Since the distance between the rotor and stator is usually 10 to 20 percent of the blade chord, the aerodynamic interference between them has to be considered for a proper evaluation of the aerothermodynamic performance of the stage. A unified approach to the aerodynamics of the incompressible flow through a stage is presented that uses the lifting surface theory for a compressor cascade of arbitrary camber and thickness distribution. The effects of rotor stator interference are represented as a linear function of the rotor and stator flows separately. The loading distribution on the rotor and stator flows separately. The loading distribution on the rotor and stator blades and the interference factor are determined concurrently through a matrix iteration process

Acoustic pressures emanating from a turbomachine stage

A knowledge of the acoustic energy emission of each blade row of a turbomachine is useful for estimating the overall noise level of the machine and for determining its discrete frequency noise content. Because of the close spacing between the rotor and stator of a compressor stage, the strong aerodynamic interactions between them have to be included in obtaining the resultant flow field. A three dimensional theory for determining the discrete frequency noise content of an axial compressor consisting of a rotor and a stator each with a finite number of blades are outlined. The lifting surface theory and the linearized equation of an ideal, nonsteady compressible fluid motion are used for thin blades of arbitrary cross section. The combined pressure field at a point of the fluid is constructed by linear addition of the rotor and stator solutions together with an interference factor obtained by matching them for net zero vorticity behind the stage

A Rare Giant Pleural Thymoma in Posterior Mediastinum.

Thymoma is an epithelial neoplasm of the thymus, which commonly lies in the anterior mediastinum. Unusually, thymomas can also be found in other locations. Surgical excision, when feasible, appears to provide good results. We encountered a rare case of a thymoma that developed in the right thoracic cavity, and originating from the pleura in posterior mediastinum. We describe the clinical scenario, investigations, and our management of the patient

An analysis for the sound field produced by rigid wide cord dual rotation propellers of high solidarity in compressible flow

An unsteady lifting service theory for the counter-rotating propeller is presented using the linearized governing equations for the acceleration potential and representing the blades by a surface distribution of pulsating acoustic dipoles distributed according to a modified Birnbaum series. The Birnbaum series coefficients are determined by satisfying the surface tangency boundary conditions on the front and rear propeller blades. Expressions for the combined acoustic resonance modes of the front prop, the rear prop and the combination are also given

Shock tube study of the fuel structure effects on the chemical kinetic mechanisms responsible for soot formation, part 2

Soot formation in oxidation of allene, 1,3-butadiene, vinylacetylene and chlorobenzene and in pyrolysis of ethylene, vinylacetylene, 1-butene, chlorobenzene, acetylen-hydrogen, benzene-acetylene, benzene-butadiene and chlorobenzene-acetylene argon-diluted mixtures was studied behind reflected shock waves. The results are rationalized within the framework of the conceptual models. It is shown that vinylacetylene is much less sooty than allene, which indicates that conjugation by itself is not a sufficient factor for determining the sooting tendency of a molecule. Structural reactivity in the context of the chemical kinetics is the dominant factor in soot formation. Detailed chemical kinetic modeling of soot formation in pyrolysis of acetylene is reported. The main mass growth was found to proceed through a single dominant route composed of conventional radical reactions. The practically irreversible formation reactions of the fused polycyclic aromatics and the overshoot by hydrogen atom over its equilibrium concentration are the g-driving kinetic forces for soot formation

Method for the determination of the three-dimensional aerodynamic field of a rotor-stator combination to compressible flow

Using the lifting surface theory and the acceleration potential method for the flow field of an axial turbocompressor stage, a recursive and a direct method are presented that make use of the eigenfunction solutions of the isolated rotor and stator to solve for the rotor-stator interaction problem. The net pressure distribution on the rotor and stator blades is represented by modified Birnbaum series, whose coefficients are determined using a matrix procedure and satisfying the boundary conditions on the surface of the blades. The relation between the matrix operators of the recursive and the direct methods is also shown. Expressions have been given for the blade circulation, the axial and tangential forces on the blade, the rotor power required, and the induced upwash velocity of the stage

Evaluation of Bacteriological Water Quality, Bangalore-In View of Public health.

From a public health perspective, access to sufficient amounts of clean and safe drinking water is a crucial issue. The provision of good quality household drinking water is often regarded as an important means of improving health. The study was undertaken to analyze the bacterial water quality in Bangalore district, Karnataka. The bacteriological analysis was carried out using the multiple tube technique (MPN- Most Probable Number) for detection of faecal coliform and subsequently organisms present in the sample of water were identified following standard methods. The identified organisms include E. coli, Staphylococcus species, Citrobacter species, Enterobacter, Klebsiella pneumonia, Proteus species, Pseudomonas, Serratia species. 60% of the isolated organism being of the family Enterobacteriaceae. The total heterotrophic plate count (THPC) gave a range of 1.5*104 to 2.2*104 CFU/ml while the total coliform plate count (TCPC) gave a range of 2*103 to 8.3*103 CFU/ml. The presumptive faecal coliform ranged between 0-180 coliform per 100 ml. E. coli / fecal coliform were detected in 60 % of the water sample

Water quality studies of Hoskerehalli lake of Bangalore, Karnataka

The aim of the current study was to evaluate the status of the Hoskerehalli lake water with respect to different physicochemical parameters [pH, temperature, total dissolved solids (TDS), turbidity, electrical conductivity (EC), total hardness (TH), alkalinity, dissolved oxygen (DO), biological oxygen demand (BOD), chemical oxygen demand (COD), phosphate, sulphate, nitrate and potassium] during the year 2005. These parameters were compared with water quality standards to indicate probable pollution. However, the overall water quality of the lake remained within the safe limits throughout the study period. Correlation coefficient matrix between each parameter were estimated to throw light on relationship between different physicochemical parameters under investigation, few parameters like pH - temperature (r = 0.712), TDS - turbidity (r = 0.800), TDS - conductivity (r = 0.988), turbidity - conductivity (r = 0.781), temperature - alkalinity (r = 0.822), sulphate - potassium (r = 0.724) showed good positive correlation. The lake water quality is good and fit for irrigation and fish culture purpose