WINCOF-I code for prediction of fan compressor unit with water ingestion

The PURDUE-WINCOF code, which provides a numerical method of obtaining the performance of a fan-compressor unit of a jet engine with water ingestion into the inlet, was modified to take into account: (1) the scoop factor, (2) the time required for the setting-in of a quasi-steady distribution of water, and (3) the heat and mass transfer processes over the time calculated under 2. The modified code, named WINCOF-I was utilized to obtain the performance of a fan-compressor unit of a generic jet engine. The results illustrate the manner in which quasi-equilibrium conditions become established in the machine and the redistribution of ingested water in various stages in the form of a film out of the casing wall, droplets across the span, and vapor due to mass transfer

The WINCOF-I code: Detailed description

The performance of an axial-flow fan-compressor unit is basically unsteady when there is ingestion of water along with the gas phase. The gas phase is a mixture of air and water vapor in the case of a bypass fan engine that provides thrust power to an aircraft. The liquid water may be in the form of droplets and film at entry to the fan. The unsteadiness is then associated with the relative motion between the gas phase and water, at entry and within the machine, while the water undergoes impact on material surfaces, centrifuging, heat and mass transfer processes, and reingestion in blade wakes, following peal off from blade surfaces. The unsteadiness may be caused by changes in atmospheric conditions and at entry into and exit from rain storms while the aircraft is in flight. In a multi-stage machine, with an uneven distribution of blade tip clearance, the combined effect of various processes in the presence of steady or time-dependent ingestion is such as to make the performance of a fan and a compressor unit time-dependent from the start of ingestion up to a short time following termination of ingestion. The original WINCOF code was developed without accounting for the relative motion between gas and liquid phases in the ingested fluid. A modification of the WINCOF code was developed and named WINCOF-1. The WINCOF-1 code can provide the transient performance of a fan-compressor unit under a variety of input conditions

METCAN: The metal matrix composite analyzer

Metal matrix composites (MMC) are the subject of intensive study and are receiving serious consideration for critical structural applications in advanced aerospace systems. MMC structural analysis and design methodologies are studied. Predicting the mechanical and thermal behavior and the structural response of components fabricated from MMC requires the use of a variety of mathematical models. These models relate stresses to applied forces, stress intensities at the tips of cracks to nominal stresses, buckling resistance to applied force, or vibration response to excitation forces. The extensive research in computational mechanics methods for predicting the nonlinear behavior of MMC are described. This research has culminated in the development of the METCAN (METal Matrix Composite ANalyzer) computer code

Framework for evaluating the economic efficiency of a cooperative sheep slaughter house at Bangalore, India

Expansion and/or improvement of the two existing slaughter houses will not solve the problem of supplying high quality meat to the ever-growing population of the city of Bangalore. Consolidation of the entire operations of slaughtering, dressing, distribution, and of the ownership of the animals and products under a cooperative arrangement appears to be a better situation. The overall objective of this study is to provide information and develop cost data pertaining to the construction and equipping of a model slaughter house for the Bangalore area that is designed like the packing houses presently existing in the United States of America. The specific and detailed objectives are these: 1. To describe in sufficient detail the physical and technical specifications of a new slaughterhouse adapted to the needs of the Bangalore market area. 2. To describe the methodological approach to the measurement of various costs associated with the assembling, slaughtering, and dressing operations for sheep. 3. To develop the cost functions associated with the operation of the proposed model plant at varying rates of utilization. 4. To present the appropriate theoretical framework for evaluating the economic efficiency of plant operation. 5. To indicate the steps needed to set up a cooperative stockyard in the vicinity of the slaughter house and a cooperative organization to operate the model slaughter house, It is presumed that the basic approach of the model plant and organization can then be applied to other areas, time periods, and local conditions by altering the prices of plant inputs and other factors to satisfy the conditions that are associated with the different situations

A Network Flow Model for Irrigation Water Management

Irrigation water management plays a crucial role in the growth and prosperity of countries like India. Optimization Techniques can be effectively used in the management of irrigation water. Motivated by a real crisis in Andhra Pradesh, India, the authors made an attempt to provide scientific solution to the problem of management of Pennar Delta System of Nellore District in Andhra Pradesh. The problem concerns the management of water distribution and scheduling for given requirements and availabilities of water at various nodes of the irrigation network of the system. This article provides a model and framework for the problem in question. The problem is formulated as a dynamic minimum cost network flow problem and provides an approach to solve the problem using static network flow models. A need based software is also developed to solve the network flow problems. Some issues in the programming are discussed

Developing and restructuring regulated markets in Mysore State, India: an alternative for improving the efficiency of marketing food grains

The purpose of the study was to analyze how the regulated markets in Mysore State might be developed and restructured as one alternative to improve the efficiency of marketing food grains. Only secondary data was used for the study. Most of the data were derived from the publications of the State Marketing Department, Department of Agriculture, Bureau of Economics and Statistics and the University of Agricultural Sciences in Mysore State. The study consisted of five objectives all interrelated with one another. The first objective was to identify the major defects in the existing regulated markets relating to their structure, methods of price determination, weighing and grading, storage, and methods of operation, to develop a model design of physical facilities needed and to outline the operational procedures for their efficient functioning. The second objective was to identify the causes of low arrivals in some regulated markets and suggest an optimum pattern for location of regulated markets. The third objective was to suggest a uniform staffing pattern for all regulated markets essential for their efficient functioning. The fourth objective was to propose a model State Agricultural Marketing Board to supervise the activities of regulated markets in the state. The fifth objective was to set up a Market Development, Research and Survey unit to carry out research in the field of agricultural marketing. With these objectives in view, first, an estimate of food grains to be moved into urban areas in the next 15 years was made to indicate the magnitude of agricultural marketing problems. Next, a model design of physical facilities needed and the operating personnel required for a regulated market, along with operational procedures for efficient functioning, were outlined. Based on the area under cultivation, area under irrigation, and marketable surplus available in each of the 19 districts, a pattern for the relocation of regulated markets along with their areas of coverage assuming a 15 mile radius for each market was illustrated by figures. It was considered that 107 regulated markets were sufficient for the state as against the existing 155 regulated markets for the whole state. In view of the huge sums of public money involved in the operations of regulated markets, a State Agriculture Marketing Board was found necessary to supervise their activities. Hence, a model for establishing a board along with its functions and powers was outlined. Considering the importance of research in improving the efficiency of marketing food grains, a model framework for a Market Development, Research and Survey unit at the state level, along with a list of important research projects to be undertaken by this organization, was indicated. Finally, an attempt was made to outline how the Farmers Cooperatives, the Food Corporation of India, and private trade could coordinate with a network of well organized regulated markets with the sole objective of improving the efficiency of the marketing system for food grains in Mysore State

Optimal fabrication processes for unidirectional metal-matrix composites: A computational simulation

A method is proposed for optimizing the fabrication process of unidirectional metal matrix composites. The temperature and pressure histories are optimized such that the residual microstresses of the composite at the end of the fabrication process are minimized and the material integrity throughout the process is ensured. The response of the composite during the fabrication is simulated based on a nonlinear micromechanics theory. The optimal fabrication problem is formulated and solved with non-linear programming. Application cases regarding the optimization of the fabrication cool-down phases of unidirectional ultra-high modulus graphite/copper and silicon carbide/titanium composites are presented

Metal matrix composite micromechanics: In-situ behavior influence on composite properties

Recent efforts in computational mechanics methods for simulating the nonlinear behavior of metal matrix composites have culminated in the implementation of the Metal Matrix Composite Analyzer (METCAN) computer code. In METCAN material nonlinearity is treated at the constituent (fiber, matrix, and interphase) level where the current material model describes a time-temperature-stress dependency of the constituent properties in a material behavior space. The composite properties are synthesized from the constituent instantaneous properties by virtue of composite micromechanics and macromechanics models. The behavior of metal matrix composites depends on fabrication process variables, in situ fiber and matrix properties, bonding between the fiber and matrix, and/or the properties of an interphase between the fiber and matrix. Specifically, the influence of in situ matrix strength and the interphase degradation on the unidirectional composite stress-strain behavior is examined. These types of studies provide insight into micromechanical behavior that may be helpful in resolving discrepancies between experimentally observed composite behavior and predicted response

Second Generation Integrated Composite Analyzer (ICAN) Computer Code

This manual updates the original 1986 NASA TP-2515, Integrated Composite Analyzer (ICAN) Users and Programmers Manual. The various enhancements and newly added features are described to enable the user to prepare the appropriate input data to run this updated version of the ICAN code. For reference, the micromechanics equations are provided in an appendix and should be compared to those in the original manual for modifications. A complete output for a sample case is also provided in a separate appendix. The input to the code includes constituent material properties, factors reflecting the fabrication process, and laminate configuration. The code performs micromechanics, macromechanics, and laminate analyses, including the hygrothermal response of polymer-matrix-based fiber composites. The output includes the various ply and composite properties, the composite structural response, and the composite stress analysis results with details on failure. The code is written in FORTRAN 77 and can be used efficiently as a self-contained package (or as a module) in complex structural analysis programs. The input-output format has changed considerably from the original version of ICAN and is described extensively through the use of a sample problem

Metal Matrix Laminate Tailoring (MMLT) code: User's manual

The User's Manual for the Metal Matrix Laminate Tailoring (MMLT) program is presented. The code is capable of tailoring the fabrication process, constituent characteristics, and laminate parameters (individually or concurrently) for a wide variety of metal matrix composite (MMC) materials, to improve the performance and identify trends or behavior of MMC's under different thermo-mechanical loading conditions. This document is meant to serve as a guide in the use of the MMLT code. Detailed explanations of the composite mechanics and tailoring analysis are beyond the scope of this document, and may be found in the references. MMLT was developed by the Structural Mechanics Branch at NASA Lewis Research Center (LeRC)