A low-speed single-stage axial-flow compressor rig was configured for tests with variable-length upstream casing struts. Two axial strut lengths were tested for their effect on the inlet flow field and stalling characteristics of the compressor under clean and distorted inlet conditions. Data were obtained from one stationary and six blade-mounted high-response pressure transducers, and from a circumferentially- traversed directional probe. The distorted inlet flow field was changed significantly by the longer struts, which effectively sectored the inlet. Deep stall was not observed for this configuration. Rather, the stalling characteristic was changed to what is termed progressive rotating stall, in which six stable stall cells and significant increases in static pressure rise were noted. A new technique for determining the number of rotating stall cells from the frequency content of stationary and rotating reference frame signals is presented. Blade pressure response as a function of aerodynamic loading is detailed. / M.S.

no abstract provided by author / Master of Science

A six-stage axial-flow compressor with a 550 feet per second tip speed and a flat operating characteristic (constant stagnation-pressure ratio at constant speed over the operating range of the compressor) was designed and tested. The design theory and test results are presented in this thesis. It was designed for a constant power input per pound of flow regardless of mass flow. The design specific weight flow was 21.1 pounds per second per square foot of frontal area with an atmospheric discharge at an overall stagnation-pressure ratio of 3.25 and an inlet hub-tip radius ratio of 0.7. In order to reach design conditions the blade setting angles were reset and the machining notches at the root of the first three rotor blades were filled. In an attempt to increase the flat operating range of the compressor, the blade setting angles of the first two stages were increased and those of the last two stages were decreased. Also, the solidity of the first rotor was decreased. / Master of Science

A preliminary theoretical and experimental investigation of the effect of velocity diagram parameters on inlet total-pressure distortions through a single-stage subsonic axial-flow compressor for incompressible flow has been conducted. The wake of 1/4-inch diameter rod, measured both upstream and downstream of a rotor, has been compared for various velocity diagrams. The measured downstream wake was also compared with the downstream wake estimated by using a derived equation subject to the assumption that (a) the undistorted and distorted flows enter the rotor with the same absolute direction, (b) the static pressures of the undistorted and distorted flows are equal at the inlet and also at the exit of the rotor, (c) the increase of blade angle of attack in the distorted flow is not sufficient to cause blade stall, and (d) the distorted flow is turned in the rotor passage to the same exit direction, relative to the rotor, as the undistorted flow.> / Master of Science

Thesis (MScEng (Mechanical and Mechatronic Engineering))--University of Stellenbosch, 2005. / The objective of the thesis is to improve the performance prediction of axial compressors, using a streamline throughflow method (STFM) code by modelling the hub and casing wall boundary layers, and additional flow mechanisms that occur within a blade row passage. Blade row total pressure loss and deviation correlations are reviewed. The effect of Mach number and the blade tip clearance gap are also reviewed as additional loss sources. An entrainment integral method is introduced to model the hub and casing wall boundary layers. Various 1-dimensional test cases are performed before implementing the integral boundary layer method into the STFM. The boundary layers represent an area blockage throughout the compressor, similar to a displacement thickness, but affects two velocity components. This effectively reduces the compressor flow area by altering the hub and casing radial positions at all stations. The results from the final STFM code with the integral boundary layer model, Mach number model and tip clearance model is compared against high pressure ratio compressor test cases. The blockage results, individual blade row and overall performance results are compared with published data. The deviation angle curve fits developed by Roos and Aungier are compared. There is good agreement for all parameters, except for the slope of deviation angle with incidence angle for low solidity. For the three compressors modelled, there is good agreement between the blockage prediction obtained and the blockage prediction of Aungier. The NACA 5-stage transonic compressor overall performance shows good agreement at all speeds, except for 90% of design speed. The NACA 10-stage subsonic compressor shows good agreement for low and medium speeds, but needs improvement at 90% and 100% of design speeds. The NACA 8-stage transonic compressor results compared well only at low speeds.

Sanden international, an automobile air conditioning compressor manufacturer, was facing a problem in its incoming material inspection procedures. Although the company had designed and was using its own sampling plan, some managers and supervisors where not confident of its reliability. Sanden recently established a goal for its total number of defects per supplier as one part per million. Achievement of this target required reviews of the existing sampling plan. The purpose of this project was to help Sandra identify the best alternatives for its incoming material inspection procedures. To do that considerations were made about the usefulness of sampling inspections, theoretical aspects of inspection sampling plans were examined, current sampling plans were analyzed and recommendations were made.

Orientador: Jorge Isaias Llagostera Beltran / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Mecanica / Made available in DSpace on 2018-08-08T17:53:07Z (GMT). No. of bitstreams: 1 Lopes_FernandodeOliveira_M.pdf: 4254683 bytes, checksum: 3714a253c99b8967319409a00b69058a (MD5) Previous issue date: 2007 / Resumo: Este trabalho apresenta o desenvolvimento de um programa computacional para modelagem inicial de compressores axiais de vários estágios pertencentes ao conjunto de turbinas a gás. O desenvolvimento do programa se baseia na metodologia adotada por Saravanamutto et al. (2001), faz uso da Primeira Lei da Termodinâmica para cálculo de potência consumida pelo compressor e da Segunda Lei da Termodinâmica para determinar o grau de irreversibilidade do sistema. O programa calcula a quantidade de estágios necessária para uma dada relação de pressão, a quantidade de palhetas por estágio e outros dados construtivos do compressor. O trabalho analisa a eficiência global de uma turbina a gás, avalia rendimento utilizando diferentes tipos combustíveis, estuda a influência da temperatura de entrada do ar no compressor, temperatura de entrada dos gases na turbina, e eficiência isentrópica do compressor e da turbina. Fatores que geram instabilidade no compressor são discutidos e algumas sugestões são apresentadas para evitar que compressores operem fora das condições iniciais. O trabalho apresenta procedimentos claros e detalhados para o préprojeto de um compressor de fluxo axial. Finalmente, o trabalho apresenta uma breve discussão sobre eficiência exergética de máquinas térmicas / Abstract: This work presents the developing of a computational program for designing axial compressors that hold multistage belonged gas turbine. The developing of the program is based on methodology adopted by Saravanamutto et al.(2001), it makes use of the First Law of Thermodynamic to calculate the power required by the axial compressor e the Second Law to calculate the level of irreversibilities. Beside of this the program presents the numbers of stages required for a given pressure ratio, the amount of blades per stage and other building parameters has been included to make a better analyze about the equipment. The work contains thermal efficiency analyzes of a gas turbines, where parameters such as fuels, temperature intlet turbine, environmental conditions, efficiency of the compressor and turbine are included. Other factors such as unstable conditions are discussed and solutions to avoid that axial compressors running in off design conditions. In summary the work provides a global view about thermal machines and how their parameters can influence both in the thermal and exergetic efficiency / Mestrado / Termica e Fluidos / Mestre em Engenharia Mecânica

M. S.

Flow visualization movies of flow through a cascade of compressor blades showed propagating stall at stagger angles of 36.5 and 45 degrees for angles of attack of 20 degrees and higher. At a stagger angle of 25 degrees, the development of a steady, separated boundary layer occurred with no propagation. The observed propagating stall process was the development of a vortex in the boundary layer and its subsequent shedding. The shedding mechanism was observed to be the interference by the reverse flow from the previously stalled passage with the vortex flow in the stalled passage. This dissipated the vortex in the blade passage and the incoming flow then flushed the stagnated vortex out of the passage. Measurements of propagation speeds showed that the propagation speed is related to the blockage of the passage, that stagger angle has an insignificant effect on propagation speed, and that propagation speed is proportional to the relative velocity. Based on the observations, a geometric model was developed to predict the onset of propagating stall. This model showed that increased solidity, decreased stagger angles, and operation at low angles of attack make a cascade more resistant to propagating stall inception. The model shows the relation of the operating point of a compressor to the stall inception point. When expanded to include all significant aspects of blade geometry, the model may provide a basis for controlling propagating, and hence, rotating, stall inception based on the blade row·geometry. / Master of Science

Pressure signals were taken on a rotor blade surface of a single-stage, low-speed axial flow compressor. The data showed unsteady, stationary pressure perturbations that correlated with the locations of five large downstream support struts. In the present work, these data are thoroughly analysed. Strut-induced pressure amplitudes as measured on the rotor are presented as a function of the downstream strut locations. Unsteady lift and moment are calculated by integrating the pressures measured by the blade-mounted transducers. In addition, a sequence of instantaneous pressure distributions on the blade surfaces presented over time shows how the rotor is influenced by the potential effect of the struts. The strut is shown to produce a significant effect on rotor flow. This effect exceeds the unsteady stator effect at design rotor-stator-strut spacing, but falls off rapidly as the struts are moved downstream. / M.S.