Information Pasteboard
Weekly reports of meetings at NAL, snippets of R&D activity, conference announcements and other features of popular interest
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Information Pasteboard |
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News and Events #IP 970 25 Apr - 1 May 2011 Report on Industry Meet on High Temperature Solar Selective Coating TechnologyCSIR-NAL has developed a high temperature solar selective coating on 6 inches long stainless steel tubes using a laboratory scale sputtering process. This coating exhibits promising optical properties (absorptance of 0.930 and emittance of 0.17-0.18 on stainless steel substrates) and is found to be stable in vacuum for 1000 hrs at 450°C under cyclic heating conditions. The coating, which is developed indigenously, has a great potential for applications in parabolic trough receiver tubes and also for a variety of other industrial process heat applications. In order to scale up CSIR-NAL coating technology for industrial applications, it is proposed to set up a sputtering facility at NAL for the deposition of high temperature solar selective coating on two m long stainless steel tubes with financial support from CSIR and MNRE under CSIR Program on Solar Energy (TAP-SUN). In this respect an Industry Meet was convened on April 20, 2011 at NAL. A total of 40 delegates (17 from the Industry) participated in the Industry Meet. The industries which participated in the Industry meet were: KG Design Services Pvt. Ltd., Coimbatore, Lanco Solar Pvt. Ltd., Gurgaon, Thermax, Pune, Space-age, Bangalore, Maharaja Techno Chromes Pvt. Ltd., Bangalore, Nice Technologies, Bangalore, Vacuum Techniques Pvt. Ltd., Bangalore, Bhagyanagar India Ltd., Secunderabad, Centre for Study of Science, Technology and Policy, Bangalore, 3M India Ltd., Bangalore, Maharishi Solar Technology Pvt. Ltd., New Delhi, Tata BP Solar India Ltd., Bangalore and Milman Thin Film Systems Pvt. Ltd., Pune. The inaugural session started with a welcome address by Dr. (Mrs.) K. S. Rajam, Head, Surface Engineering Division followed by an introduction about the meet by Mr. M. K. Sridhar, Chairman, Structure and Materials Cluster, NAL. Dr. A. R. Upadhya, Director, NAL in his opening remarks suggested that the industries should come forward to work with NAL. He emphasized that the high temperature solar selective coated tubes are one of the major components of a solar thermal power plant. Therefore, it is necessary that NAL’s laboratory scale coating technology should be scaled up to 2 m long tubes by setting up an industrial sputtering facility at NAL. This sputtering system will be available to NAL as a research and technology development tool. He suggested that NAL would address engineering issues related to the development of an industrial sputtering system for the deposition of high temperature solar selective coatings on two m long tubes but emphasized that the commercial production for this technology should be taken up by the industry. However, after the successful demonstration of coating technology on two m long tubes industries can use and run the NAL sputtering facility. Dr. B. Bandopadhyay, Advisor, Solar Thermal Group, MNRE, New Delhi outlined the objectives of National Solar Mission. He said that the high temperature solar selective coating technology is one of the most important technologies for the development of solar thermal power plants. He invited industries to work with NAL and MNRE for scaling up NAL’s high temperature solar selective coating technology. He also suggested that the industry should contribute financially for this project in order to demonstrate their firm commitment. He said a huge market has been created by the government in the solar power generation sector as the ministry wishes to generate approximately 20000 MW solar power by 2022. Prof. S. Srinivasa Murthy, IIT Madras, Chennai and Chairman, Committee on Solar Thermal R&D Projects, MNRE, New Delhi, gave an overview of solar thermal power scenario in India. He emphasized that indigenous development of critical technologies related to solar power generation is essential for self reliance. Given the fact India has tremendous potential for solar energy, Prof. Murthy pointed out that India should be a leader and not the follower in area of solar thermal power generation. Dr. Harish Barshilia, Scientist, SED delivered a detailed technical presentation on the state-of- the-art on solar thermal power generation and also on the research carried out by NAL in the area of high temperature solar selective coating technology. He also presented the road map for setting up the technology and facility for the development of high temperature solar selective coating on two m long tubes. In the afternoon session, a lab visit was arranged for the industry participants. Subsequently, discussion session was held in which the industry participants were asked to provide the feedback on the Industry Meet and also put forward their view points. Dr. S. P. Viswanathan, President, K. G. Industries made a brief presentation on the need for developing a suitable solar selective coating technology in India and mentioned that K. G. Industries immediately require approximately 4000 m long tubes coated with high temperature solar selective coating for their MNRE sponsored project on linear Fresnel technology to be set up very soon at Solar Energy Centre, Gwal Pahari, Gurgaon. He mentioned that at present K. G. Industries are using NALSUN coated tubes for producing superheated steam at their facility in Coimbatore. Furthermore, Dr. Viswanathan pointed out that the indigenous development of the high temperature solar selective coated tubes will bring down the cost by a factor of approximately five. He suggested that MNRE, KG Design Services and NAL should work together to develop the high temperature solar selective coated tubes. Mr. Prasad, Senior Vice-President, Lanco Solar Pvt. Ltd., suggested that equal opportunity should be given to all the industries for know-how transfer on NAL’s high temperature solar selective coated tubes. Dr. Vinay Tiwari from Thermax, Pune, suggested that NAL should work towards reducing the emittance of the coating developed and cost of the coated tubes. He also pointed out that NAL should work on sol-gel based solar selective coating technology, which is a very cost effective process. Dr. Tiwari informed that Thermax is setting up state-of-the-art facilities for the measurement of various properties of solar selective coatings with financial support from DST. Mr. Jayaramu, Space-age, Bangalore suggested that NAL should also work on PVD based mid-temperature solar selective coatings as a replacement of black chrome technology. The meeting concluded with closing remarks by Mr. M. K. Sridhar, Chairman, Structure and Materials Cluster, NAL, Dr. B. Bandyopadhyay, Advisor, MNRE and Dr. A. R. Upadhya, Director, NAL. Harish C. Barshilia
Photo and photo collage designed by Team Photography, KTMD, NAL
#IP 969 18 - 24 Apr 2011 Wind Profiling for Energy Harvesting A talk on “Wind Profiling for Energy Harvesting” by Dr. U.N Sinha, Distinguished Scientist, at CSIR-NAL was organized by the Centre for Societal Missions and Special Technologies (CSMST) on March 30, 2011.The aim was to call for a synergic effort of various divisions of CSIR-NAL like CSMST, CTFD and FLOSOLVER so that wind energy provides a win-win situation for both the wind turbine operators as well as for the consumers. In his welcome address, Dr. G.N Dayananda, Head, CSMST introduced the speaker, who holds a bachelor’s degree in Mechanical engineering from Bhagalpur University and a Ph.D. from IIT Kanpur. He joined NAL in 1972, and since then has worked on diverse areas such as aircraft aerodynamics, gas dynamic lasers, atmospheric sciences and computers. Dr. Sinha is the brain behind the supercomputer ‘FLOSOLVER’ - India’s first parallel computer. Dr. Sinha began his talk with a simple calculation to derive the earth’s rotational velocity and then explained its effect on atmospheric dynamics; the other part of the lecture was devoted to understanding the importance of Coriolis component: he first derived the expression, and then explained its physical significance in determining the motion of high clouds in the sky, which, to the surprise of many, move along constant pressure surfaces and, not as commonly thought, from high to low pressure. Before requesting Dr. J. J Isaac to take over, Dr. Sinha shared his dream of having a ‘virtual wind turbine’ which will house CFD resources and could be deployed for simulating the effects of atmospheric boundary layer on wind turbines. Dr.Isaac put into perspective the wind turbine design aspects and how meteorological sciences and wind farm design should go hand in hand. He was of the view that conventional wind turbine designs may no longer be the best if higher velocity regions in the atmospheric boundary layer were to be taken advantage off. Towards the end there was an informal session which saw Dr. Mudkavi, Head, CTFD observing that the problem of wind farm aerodynamics seemed to be that of ‘inverse optimization’, while Dr. B.R Basu, the meteorological scientist with FLOSOLVER, laid stress on conducing field trials at a given location. Prof. Vasudeva Murthy from TIFR and others from the audience also gave their points of view. #IP 968 11-17 Apr 2011 The Acoustic Test Facility at ISITE complex Dr. K. Radhakrishnan, Chairman, ISRO / Secretary DOS inaugurated the state-of-the art “ISITE ACOUSTIC TEST FACILITY” designed and commissioned by CSIR-National Aerospace Laboratories, Bangalore, for ISRO Satellite Centre (ISAC), Bangalore, on April 7, 2011. This facility, consisting of 1500 Cu. m Isolated Reverberation Chamber can qualify satellites up to 156dB in Nitrogen atmosphere, is largest and one-of-its kind in India. This facility will be used to perform qualification and acceptance acoustic tests of ISRO’s satellites at the ISITE campus of ISRO at Marathahally. Satellites are launched by powerful rockets with very high velocity, creating severe dynamic loads on the payloads. The acoustic field created during launch and trans-atmospheric flight can be strong enough to damage the delicate satellite/payloads, since economy of launch demands that the satellite and payload structures should be as light as possible. Once the payload crosses the atmospheric layer, it never again experiences such noise fields during its useful life. It is, therefore, essential to test on ground all payload packages for such launch-exposed energy fields for their mechanical effects under simulated conditions. The acoustic tests are designed to induce dynamic responses in the test specimen similar to those experienced in flight to qualify them under flight conditions to ensure trouble-free operation. The acoustic shielding efficiency of heat shields is also tested in this facility. Presently, the acoustic tests on satellites are being conducted at the ISRO-NAL Acoustic Test Facility located at CSIR-NAL’s Belur campus. ISAC proposed the new Nitrogen-based Acoustic Test Facility (NATF) at their ISITE complex with regards to the need for large number of acoustic tests, and with the added advantage that all tests would be conducted under one roof. Equipped with the experience in design, operation and maintenance of the existing Acoustic Test Facility, in March 2007 CSIR-NAL took the challenge to design, build and commission the NATF. The NTAF facility is fully functional with its own control room, data room, ground checkout room, air-lock area and air handling units. This facility, ninth such facility in the world, is in par with any such contemporary world acoustic test facility.
Inauguration of “ISITE ACOUSTIC TEST FACILITY” Designed and commissioned by CSIR-NAL for ISRO
Salient Features
#IP 967 4-10 Apr 2011 CSIR-NAL Develops Active Magnetic Bearing For a Vertical Sodium Pump for IGCAR, Kalpakkam Though the phenomenon of magnetic levitation was discovered as early as 1842 by Earn Shaw, the research on magnetic levitation of rotating or moving systems gained momentum in recent years with the advent of reliable electronic components. The device used for supporting a rotor by magnetic levitation is termed as Magnetic Bearing, which consists of mechanical components as well as electronic components such as sensors, power amplifiers and control circuitry. Thus, it is a mechatronics product, and the development of active magnetic bearings requires knowledge in multiple disciplines of engineering. In magnetic bearings there is no physical contact between the stator and the rotor. Owing to the absence of contact these bearings have several advantages over conventional (slider and rolling element) bearings: low power loss, no need for lubrication, no leakage problem, suitability for application in high pressure or vacuum, high-rotor speed and longer bearing life. Further, the stiffness and damping characteristics of the magnetic bearings are easily adjustable according to the requirement. Magnetic bearings can operate in a wide range of temperature from –250 C to 450 C. Application of magnetic bearings in various fields may be found in literature employing different control strategies. It is observed from the literature that development works on magnetic bearings have been carried out mostly abroad. However, a few research groups within the country are involved in the development of magnetic bearings, and The Propulsion Division of CSIR-NAL is one of the pioneering research groups working on magnetic bearings. Research activities have been carried out towards indigenous development of active magnetic bearing technology at CSIR-NAL, leading to successful demonstration of 5-axes levitation of a rotor weighing 5 kg and speed up to 10000 rpm. In recent years there have been instances of the use of magnetic bearings in nuclear reactor systems. Vertical centrifugal Sodium Pumps are used for circulation of coolant in the primary and secondary circuits of fast reactors for nuclear power plants. Lubrication oil leakage from the conventional bearings used in these pumps is a potential threat to cause reactivity changes which could culminate in extended reactor shut down. Actively controlled magnetic bearings which do not require lubrication is an excellent alternative to conventional bearings in overcoming these problems. A development program was initiated towards this goal by CSIR-NAL in collaboration with IGCAR, Kalpakkam. It was decided to indigenously develop the active magnetic bearings to be retro-fitted to an existing centrifugal pump of 50 m3/h capacity at IGCAR. The research effort basically involved development of “thrust and radial active” magnetic bearings catering to a thrust load of around 1050N, and a nominal radial load for the existing vertically- configured shaft system of the centrifugal pump, and its demonstration at 2900 rpm under simulated conditions, followed by commissioning of the bearing system on-site at IGCAR. This required the development of actuators and a direct feedback control system for radial and thrust magnetic bearings, ensuring proper stiffness in the bearing planes from rotor dynamics point of view, resulting in smooth running of the shaft system up to the design speed. During the course of this development a successful attempt to realise improved actuator response was also made, and it lead to the filing for a patent (Ref: 0613 DEL 2009) and an innovative design for the thrust disc have been realised (discussions are on to obtain a copy right on the design).The application of active magnetic bearings for centrifugal pump under simulated conditions was successfully demonstrated in the presence of Scientists of IGCAR at CSIR-NAL before successfully commissioning of the same at IGCAR, Kalpakkam (Figure 1). Performance of the active magnetic bearings has been tested successfully by running the pump up to the full operating speed of 2900 rpm; the measured vibration levels were well within the allowable limits (Figure 2).
Fig. 2 Measured Vibrations for Thrust (t1, t2, t3, t4) and Radial (r1, r2) AMB Sensors Recent issues of NAL Information Pasteboard Prev To
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