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Venugopal, S.
- Combustion Experiments of HTPB/RFNA Mixed Hybrid Propellants
Authors
1 Defence Research and Development Laboratory, Hyderabad – 500 058
Source
Indian Journal of Science and Technology, Vol 4, No 10 (2011), Pagination: 1267-1272Abstract
A series of combustion experiments have been conducted for investigating the regression rates of mixed hybrid propellants using Red Fuming Nitrous Acid (RFNA) as liquid oxidizer and Hydroxyl-Terminated Polybutadiene (HTPB) with the addition of Ammonium Perchlorate (AP) upto 20 percent as the solid fuel. HTPB is the state-of-theart binder used in solid propellant rocket motors and is considered to be a potential candidate fuel for hybrid rocket applications due to its higher regression rate characteristics, greater fuel value, higher carbon/hydrogen ratio and solid loading capability. One of the effective ways of increasing the regression rates in hybrids is the addition of solid oxidizer such as AP in the fuel in small percentages. This type of configuration is called "mixed hybrid" and regression rate enhancement upto 100% is obtained. A series of static tests are conducted to establish the ignition and combustion in the hybrid mode. It is seen that the hybrid propellant has burnt smoothly. The ignition pressure could also be controlled and kept to a reasonable value. Stable combustion within a variation of chamber pressure ±2% and combustion efficiency above 0.95 was achieved. The characteristics of the combustion products are calculated using the NASA CEA code. Regression rate correlations for the different combinations are obtained using the experimental data and ballistic code developed for predicting the performance of hybrid system.Keywords
Hybrid, Regression Rate, Mass Flux, Specific Impulse, Solid Fuel, Liquid OxidizerReferences
- Frederick Jr RA, Whitehead JJ, Knox LR and Moser MD (2007) Regression Rates Study of Mixed Hybrid Propellants. AIAA J. Propulsion Power. 23(1), 175- 180.
- McBride BJ and Gordon S (1996) Computer Program for Calculation of Complex Chemical Equilibrium Compositions and Applications: II. Users Manual and Program Description. NASA Ref. Publ. pp: 1311,
- George P and Krishnan S (2001) Fuel Regression Rate in Hydroxyl-Terminated-Polybutadiene/ Gaseous Oxygen Hybrid Rocket Motors. AIAA J. Propulsion Power, 17(1), 35-42.
- Fraunhofer-Institut für Chemische Technologie Computer Code Version-3 (2001) ICT Database of Thermochemical Values.
- Wernimont EJ and Heister SD (2000) Combustion Experiments in Hydrogen Peroxide/Polyethylene Hybrid Rocket with Catalytic Ignition. AIAA J. Propulsion Power 16(2), 318-325.
- Solving Travelling Salesman Problem and Mapping to Solve Robot Motion Planning through Genetic Algorithm Principle
Authors
1 School of Computing, SASTRA University, Thanjavur - 613401 Tamil Nadu, IN
2 Indira Gandhi Centre for Atomic Research, Kalpakkam - 603102, Tamil Nadu, IN
Source
Indian Journal of Science and Technology, Vol 8, No 35 (2015), Pagination:Abstract
Travelling Salesman Problem (TSP) is a very old problem which has been solved in so many methodologies. The solution for the Robot Path Planning (RPP) can be derived using the methodologies used for the TSP. In this paper, Genetic Algorithm (GA) principle is employed to solve the TSP and is mapped to solve the RPP with the same principle. The both problems are defined to observe similarity between these problems and enumerated the conversion phases. In these two cases how the solutions are to be derived to implement the GA technique to accomplish the optimal path in both cases and tested for different number of cities, population space and generations. The minimum cost and mean cost of the solution space proves its giving the optimal resultKeywords
ASCII, Encryption, Hackers, Random Number, Symmetric Key- Layered Approach for Three Dimensional Collision Free Robot Path Planning using Genetic Algorithm
Authors
1 School of Computing, SASTRA University, Thanjavur - 613401, Tamil Nadu, IN
2 Indira Gandhi Centre for Atomic Research, Kalpakkam - 603102, Tamil Nadu, IN
Source
Indian Journal of Science and Technology, Vol 8, No 35 (2015), Pagination:Abstract
Robot Path Planning (RPP) is solved using Genetic Algorithm (GA) principle for collision-free navigation for the three dimensional static space to find the optimal path. In this paper, Layered Approach is employed where the whole three dimensional space is considered as layers of two dimensional spaces to accomplish the RPP to reach the target by avoiding obstacles and find the shortest path. The quality of the path is ensured by nearest neighbourhood approach. Implementation of the principle of GA to solve RPP is effective where the environment contains huge number of solution paths compared to the classical methods to obtain the shortest path from source to target. This approach is tested for different number of layers and the results are tabled. The path generated and optimal path obtained by the implementation of this approach has been compared with the cost of the optimal path obtained manually.Keywords
Collision-Free, Genetic Algorithm, Robot Path Planning, Three Dimensional Spaces- Forming Limit Diagram for Austenitic Stainless Steels
Authors
1 Department of Production Technology, Madras Institute of Technology, Chrompet, Anna University, Chennai-600044, IN
2 Metal Forming and Tribology Section, Indira Gandhi Center for Atomic Research, Kalpakkam, IN
3 Department of Mechanical Engineering, St. Joseph’s College of Engineering, Chennai-600119, IN
Source
Manufacturing Technology Today, Vol 7, No 4 (2008), Pagination: 27-32Abstract
Austenitic stainless steels are special grades of steels with improved corrosion resistance and oxidation resistance. In this work forming limit diagrams (FLDs) for Austenitic stainless steels of grades AISI 316 and 316L of thickness 1.25mm have been studied and their suitability for forming applications have been examined. FLDs were experimentally found using the hemispherical punch forming test. The micro structural aspects, tensile properties, formability parameters of the above mentioned steels were studied and compared. The fracture surfaces of the formed samples were viewed using the scanning electron microscope (SEM) and the SEM images were correlated with the fracture behavior and formability of the sheet metal. It was found that the formability of AISI 316L posses good drawability and stretchability.- Development of Brazed Joints Using Induction Heating System for High Temperature Nuclear Applications
Authors
1 Group for Remote Handling, Robotics, Irradiation. Experiments and Post Irradiation Examination (GRIP), Metallurgy and Materials Group (MMG), Indira Gandhi Centre for Atomic Research (IGCAR), Kalpakkam- 603 102, Tamilnadu, IN
Source
Indian Welding Journal, Vol 44, No 2 (2011), Pagination: 43-53Abstract
Fabrication of instrumented capsule for irradiation experiments for evaluating the irradiation performance of fuel and structural materials in a nuclear reactor requires development of thin-walled joints capable of withstanding high temperature and internal pressure. Instrumented capsules are being developed in IGCAR for irradiation of fuel and structural material specimens in Fast Breeder Test Reactor (FBTR). Instrumented capsule for irradiation of fuel pin specimen will have thermocouple of diameter 1 to 1.5 mm passing through the end plug of the fuel pin in a leak tight manner to prevent the release of fission gases generated in the fuel pin that may reach a pressure upto 10 MPa at 550°C during reactor operation. Out of the various joining methods, development of high temperature brazed joint method is found to be beneficial with respect to sealing the thermocouple passing through the end plug of the fuel pin and the intermediate plug of the irradiation capsule. Furnace and induction brazing methods have been tried and induction brazing method is seen to be more suitable for the present application. A procedure has been established to properly orient and braze the thermocouples in stainless steel plugs representing end plug and intermediate plug. Brazing parameters like temperature, time, vacuum level, and the brazing gap width are important factors in achieving good quality brazing joints. The trials carried out and the results obtained are discussed in this paper.
Keywords
Instrumented Fuel Irradiation Capsule, High Temperature Brazing, Induction Heating.- Laser Welding of Precision Engineering Components
Authors
1 Group for Remote Handling, Robotics, Irradiation Experiments and Post Irradiation Examination (GRIP), Metallurgy and Materials Group (MMG), Indira Gandhi Centre for Atomic Research (IGCAR) Kalpakkam- 603 102, IN
Source
Indian Welding Journal, Vol 44, No 2 (2011), Pagination: 54-59Abstract
Laser beam welding (LBW) with its high power density produces narrow and deep welds with a small heat-affected zone. Nd-YAG laser has been used extensively in the fabrication of small precision components at Indira Gandhi Centre for Atomic Research (IGCAR). Some important laser welding works carried out are related to Eddy Current based Position Sensor (ECPS) and Sodium Leak Detector (SLD) in Diverse Safety Rod Drive Mechanism (DSRDM) of Prototype Fast Breeder Reactor (PFBR), and components for Ir-192 High Dose Rate (HDR) source for Board o f Radiation and Isotope Technology (BRIT). ECPS is being designed to incorporate in the DSRDM to provide a measurement on signal which indicates that all the safety rods are dropped in case of a reactor scram signal. Mineral insulated (MI) cable of 1 mm diameter used as the eddy current coil in the ECPS has been terminated with suitable end configuration using laser welding. SLD is housed inside the electromagnet assembly of DSRDM to indicate if there is any leakage of sodium into the electromagnet. The fabrication of SLD requires precision laser welding of a few of its components. For the indigenous development of Ir-192 source assembly for use in HDR Branchy therapy, the feasibility study has been carried out for the fabrication of the miniature source holder by laser welding process. This paper discusses the techniques followed in the successful fabrication of above mentioned variety of intricate components used in critical applications.
Keywords
Nd-YAG Laser Welding, Precision Components, PFBR, ECPS, DSRDM, Sodium Leak Detector, HDR Source.- Fatigue of Welded Components and Structures-Current Status
Authors
1 Indira Gandhi Centre for Atomic Research, KALPAKKAM, IN