Attention was tocused on the simple turbojet units where low power- plant weight was of great importance. Since the war, however, the axial compressors have been developed to the point where t has an appreciably higher Isentropic efficiency. Though centrifugal compressors are not that popular today, there is renewed interest In the centrifugal stage, used In conjunction with one or more axial 1 | Page A centrifugal compressor essentially consists of three components. 1 . A stationary casing 2. A rotating impeller as shown in Fig. which imparts a high velocity to the air. . A diffuser consisting of a number of fixed diverging passages in which the air is decelerated with a consequent rise in static pressure. Figure: Schematic views of a centrifugal compressor Applications 1. In gas turbines and auxiliary power units In their simple form, modern gas turbines operate on the Brayton cycle. Either or both axial and centrifugal compressors are used to provide compression. The types of gas turbines that most often include centrifugal compressors include turbo shaft, turboprop, auxiliary power units, and micro-turbines.
The industry standards applied to all of the centrifugal compressors used in aircraft applications are set by the FAA and the military to maximize both safety and durability under severe conditions. . In automotive engine and diesel engine turbochargers and superchargers . Centrifugal compressors used in conjunction with reciprocating internal combustion engines are known as turbochargers. 3. In pipeline compressors of natural gas to move the gas from the production site to the consumer. Centrifugal compressors for such uses may be one- or multi-stage and driven by large gas turbines.
Standards set by the industry (ANSI/API, ASME) result in large thick casings to maximize safety. The impellers are often if not always of the covered style which makes them look much like pump impellers. This type of ompressor is also often termed an API-style. 2 | Page 4. In oil refineries, natural gas processing, petrochemical and chemical plants. Centrifugal compressors for such uses are often one-shaft multi-stage and driven by large steam or gas turbines. Their casings are often termed horizontally split or barrel. 5.
Air-conditioning and refrigeration and HVAC: Centrifugal compressors quite often supply the compression in water chillier cycles. Because of the wide variety of vapor compression cycles and the wide variety of workings gases , centrifugal compressors are used in a wide range of sizes and configurations. Advantages and Disadvantages Centrifugal-flow compressors have the following advantages: * High pressure rise per stage. * Efficiency over wide rotational speed range. * Simplicity of manufacture with resulting low cost. * Low weight.
They have the following disadvantages: * Large frontal area for given airflow. * Impracticality if more than two stages because of losses in turns between stages. Axial Compressor An axial compressor is a pressure producing machine. It is a rotating, air foil-based compressor in which the working fluid principally flows parallel to the axis of rotation. This is in contrast with other rotating compressors such as centrifugal compressors, axe-centrifugal compressors and mixed-flow compressors where the air may enter axially but will have a significant radial component on exit.
The energy level of air or gas flowing through it is increased by the action of the rotor blades which exert a torque on the fluid which is supplied by an electric motor or a steam or a gas turbine. Figure: Axial compressor 3 | Page Axial compressors consist of rotating and stationary components. A shaft drives a central drum, retained by bearings, which has a number of annular air foil rows ttached usually in pairs, one rotating and one stationary attached to a stationary tubular casing. A pair of rotating and stationary air foils is called a stage.
The rotating air foils, also known as blades or rotors, accelerate the fluid. The stationary air foils, also known as stators or vanes, convert the increased rotational kinetic energy into static pressure through diffusion and redirect the flow direction of the fluid, preparing it for the rotor blades of the next stage. The cross-sectional area between rotor drum and casing is reduced in the flow direction to maintain an optimum Mach umber using variable geometry as the fluid is compressed. 1 .
Successful creativity, innovation and design thinking activities within organizations are dependent on the work of individual employees only
Successful creativity, innovation and design thinking activities within organizations are dependent on the work of individual employees only.
You are required to write an argumentative academic essay of 1500 words (excluding reference list) on the following statement: ‘Successful creativity, innovation and design thinking activities within organizations are dependent on the work of individual employees only’. In your essay, identify and define what is meant by creativity, innovation and design thinking, whether you agree, do not agree or partially agree with the statement and why you agree/disagree/partially disagree using relevant theory. You must also use real-world corporate examples (e.g., examples from companies like Google, Tesla etc) to justify your stance.
References: should be 6 scholarly work and 4 non-scholarly work where
real-world corporate examples are used .
What is an argumentative academic essay?
An argumentative academic essay is a piece of writing that examines and interprets a given ‘claim’ or ‘statement’ and defends or refutes it with the use of theoretical and practical evidence. In such an essay, you are essentially building up and presenting your own argument(s) on the statement while using scholarly (i.e., journal articles, textbooks, theories etc.) and practical evidence (e.g., corporate stories, news items relating to companies etc) to support your arguments. Hence, you are not simply describing or summarising what others have said about a given statement but introducing and developing your own arguments on it. Your arguments must be backed by evidence if they are to be valid.
Guidelines for writing the argumentative academic essay
In writing your argumentative academic essay, you may want to follow the following guidelines:
1. Read the given statement carefully and understand what it means.
2. Use course content learned in class as well as external research done using scholarly work to further investigate the given statement. Remember to read critically on this topic so that you are able to critically evaluate what others have said about the topic and come to your own conclusions on the topic.
3. Based on the research you have carried out, decide your ‘stance’ relating to this statement. Your stance means whether you agree with it, disagree with it or partially agree with it (you may agree with some aspects of the statement but disagree with other aspects). It’s very important that the argumentative academic essay clearly expresses the writer’s stance.
4. Write your essay to include the arguments you want to set forth and use 4 – 6 scholarly work and practical examples (at least 2) to support your arguments.
Structure of the argumentative academic essay:
Your argumentative academic essay must have the following components:
1. Introduction: must include (a) the purpose of writing your essay (e.g., The purpose of writing this essay is to critically evaluate and put forth arguments on whether successful creativity, innovation and design thinking activities are only dependant on the work of individual employees)
(b) the stance taken by you (e.g., I agree with the given statement)
(c) the scope of the essay – what theories will be used in your essay, what real-world examples will be given in your essay
(d) the structure of the essay – what will you explain in body paragraph 1, what will you explain in body paragraph 2 etc.
2. Body paragraphs: Your argumentative academic essay can include 2-3 body paragraphs. You can give each paragraph a sub-heading if you wish.
In the body paragraphs, you must provide scholarly definitions of what is creativity, innovation and design is, what arguments you present to support the stance you have taken, and corporate examples as well. Remember that the stance you have written in the Introduction and the stance you take in the body paragraphs must be the same. You must also include in-text references of all scholarly work (i.e., journals, academic textbooks, e-books etc) and of non-scholarly work (i.e., company websites, newspaper articles, company videos etc) used. Non-scholarly work has to be cited when real-world corporate examples are used to support your arguments.
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