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1、指导教师 赵永成 职 称 教 授 所在单位 机械工程系机制教研室 教研室主任 董 淑 婧 完成日期 年 月 日Gas turbines-a growth industry Major developments in the filed of gas turbine technology have taken place in recent years and power units are available today that compete with diesel engines in a wide range of applications from small engines for

2、 boats, cars, light aircraft and trucks to large units for industrial and electrical generating stations. For similar output, gas turbines have the advantages of producing less noise and discharging less pollution, factors that could become increasingly significant with the growing awareness of the

3、need to protect the environment. Latest research suggests that the gas turbines are also capable of more efficient operation than their rivals. A company rapidly gaining a world-wide reputation for its pioneer work on advanced concept power pants is noel Penny Turbines Ltd, South am and Harwich. The

4、 founder and managing director, noel penny, has a high personal international reputation as an authority on small gas turbine. Although the company was established as recently as 1972, noel penny and many of his senior engineers already had many years of experience, in particular with the design, de

5、velopment and production of small industrial and automotive gas turbine at rover from 1950 onwards. Units produced were successfully used to drive pumps, generators, process plants, and hovercraft auxiliaries, etc and later ad airborne auxiliary power units in such aircraft as Vulcan, Argosy, Nimrod

6、 and Harrier. Noel Penny Turbines Ltd, is organized in three basic divisions, power plant engineering, research and development, and manufacturing. In power plant engineering, the company carries out research, design and development into advanced concept units to meet the requirements of the worlds

7、markets. Research and development is carries out both for the companys own range of products and under contract for client who will ultimately manufacture their own range. In many developments, major factors taken into consideration are cost, efficiency and ease of production. Plant available in-hou

8、se includes equipment for rig and engine evaluation up to 1000 hp, while close liaison with major Government Research Establishments and Universities provides access to sophisticated facilities where only intermittent usage is required. The company recognizes the importance of training the next gene

9、ration of engineers in the subject of gas turbine technology and thermodynamics, and has developed the NPT Turbojet instructional set. This is based on the NPT 401 engine, which is down-rated to 250 1b thrust with a fully variable throttle range from idling to maximum power. An electronic control pr

10、otects against misuse and provides a fail-safe system. The engine is pivoted in a tubular steel frame with a thrust measuring capsule incorporates in the linkage. Temperature and pressure probes at each section of the engine are connected to three abutment plates on the frame to facilitate piping an

11、d wiring to a control/instrument console. Three alternative propulsion nozzles are provided to enable the student to explore a wide range of operating characteristics. An indication of the companys standing in the field of materials and thermodynamics research is the possession of two hundred world

12、patents covering several areas of high temperature technology. In all these activities the basic aim is to improve the practical operation of the companys products. The manufacturing division has the ability to produce high quality components and the capability both to meet the requirements of Noel

13、Penny Turbines Ltd and to carry out subcontract work for clients. Machine shops, sheet metal working, welding and assembly shops are geared to prototype and small batch production of precision components and sub-assemblies. Stringent quality control and inspection standards ensure that close toleran

14、ces and high surface finishes are maintained. These arrangements are fully approved by the British Ministry of Defence Quality Assurance Board to the condition of DEF-STAN 05.21. The company is continually replacing and updating its machine tools to keep abreast of product developments and the growi

15、ng needs for machining stainless steels, Nimonics and other high temperature alloys. Included in the machine shop at Coventry are three Herbert/Devlieg Jigmils, one manually operated and two with Tape/Dialin control, used for precision machining of a wide range of components including cylinder block

16、s, gear boxes and casings in cast iron, steel and Nimonics. All the Jigmils are fitted with indexing tables to allow the maximum amount of machining at a single setting. Thin not only reduces the overall production time but helps to ensure an accurate relationship between bores and adjacent faces. A

17、 feature of the eight cylinder, V-type block in figs. 2 and 3 is the crankshaft bore in which the cylinder block is in cast iron and the bearing caps are in steel. These are bored accurately in line from both ends of the block with a 180table index between operations. The two camshaft bores are mach

18、ined in a similar way. The complete machining cycle includes multiple milling, boring, drilling and tapping operations and each cylinder block requires an overall cycle time of 180 hours. Figs.4 and 5 show a 4-cylinder in-line block being machined on a Herbert/DeVlieg 2B-36 Jigmil, while Fig. 6 show

19、s a cylinder head that was previously machined on this Jigmil. The history of Noel Penny Turbines Ltd is one of continuous growth through sound engineering development and production of a product that is being increasingly accepted ad a solution to many of tomorrows power requirements.Electronic gau

20、ging indicator with digital readoutA single dimension electronic gauging indicator with digital readout has been introduced by Herbert Sigma Ltd.Available for inch/metric indication, this new indicator operated with any of the Sigma series of linear displacement transducers and gauging heads to chec

21、k such features as length, diameter, thickness, taper, squareness and out-of-round.It is available with a choice of measuring ranges:2.0 or 0.2 and 0.2 inch or 0.02 inch reading to 0.001 and 0.0001 inch on the longer ranges and 0.001 and 0.0001 inch on the higher magnification ranges.Digital readout

22、 is provided by a red LED display featuring 10 high numerals. Signals lamps are fitted for plus （yellow）, minus （red）, and OK （green） tolerance indication.The instrument provides facilities for single transducer or for two transducers linked in sum or difference mode, while standard analogue volt-ag

23、e and current outputs are via a 12 pin socket.MTIRA open daysMore than 400 visitors saw some 34 representative exhibits and demonstrations when the Machine Tool Industry Research Association at Macclesfield opened its doors last month to show progress in machine-tool technology.Several demonstration

24、s reflected work on improving safety and in reducing the levels of noise generated by machine tools and included recordings of the noise levels emitted by a machine before and after noise reduction treatment, giving a graphic illustration of the value of the techniques developed.The Association also

25、 showed a series of rigs for testing a wide variety of guards and guarding materials. The grinding wheel guard test rig and the high-energy missile rig are massive structures and the whole complex constitutes a unique resource in the UK for the testing of guards.The Associations work in developing v

26、arious computer based design techniques and physical modeling techniques is helping to exploit the capabilities of improved cutting tools and methods.Sometimes the performance of machine tools falls short of the expectations of manufacturers or users an the Association is now skilled in the role of

27、technological detective work in identifying the causes of the problem and in recommending remedial action.MTIRA has access to world-wide data bases which allows it to offer members an information and advisory service and is also, on many occasions, able to help non-members. Prop-shaft centre quick t

28、urnround Commercial-vehicle, propeller-shaft assemblies of any diameter and torque rating can be lengthened, shortened, re-tubed or supplied complete by Tricentrol Chassis Developments Ltd at its Prop-shaft Centre at Dunstable. New equipment for welding, tube alignment and balancing has been install

29、ed, enabling the Centre to give vehicle operators repairers and even chassis manufacturers a maximum 36 hour turnaround on most types of shaft up to 6 in（150） diameter, whether of Hardy-Spicer or continental pattern. Investment in the equipment for the production and modification of prop-shafts to o

30、riginal equipment standards followed from the growing volume of business for chassis wheelbase alterations and installation of Telma retarders （which always entails shortening the vehicles prop-shaft）. The new plant comprises a GKNLincoln electric CO2 arc-welding installation, couples （on the same w

31、orked） to a special Mills tube-alignment press supplied by Alfred Herbert Ltd. The 30-ton vertical press can be used for straightening existing or new stock prop-shaft tube misalignments to within 0.003 in over the whole length. Welding of the tube ends to the universal-joint assemblies is automated

32、; the weld feed is geared to the speed of rotation of the shaft to give an even, high-quality weld seam around the shaft circumference and an automatic cut-off at the completion of 360rotation. The need for alignment correction is often indicated by whirling forces shown up on the centres dynamic balancing machine. Shaft up to 9 ft （2.74m） long can be accommodated. It is expected that the Prop-shaft Centre will also be widely used for handling non-automotive drive shafts, such as those used for powering in