Performance evaluation of an underwater body and pumpjet by model testing in cavitation tunnel

Suryanarayana, Ch.,Satyanarayana, B.,Ramji, K. The Society of Naval Architects of Korea 2010 International Journal of Naval Architecture and Oc Vol.2 No.2

Experimental investigations were carried out on an Axi-symmetric Body Model fitted with Pump-jet Propulsor (PJP) in the Cavitation Tunnel at Naval Science and Technological Laboratory (NSTL). The tests were intended for evaluating the propulsion characteristics of the body and propulsor. The self propulsion point of the model for two configurations was determined after finding the corrections for tunnel blockage effects and differences in model length at zero trim. The results were found to match closely with the towing tank results. The rotor and stator torques also matched closely over full range of experiment. Further experiments were carried out on the body at $4.5^{\circ}$ angle of trim to investigate the propulsive performance and assess the operational difficulties in the sea. The results indicated an increase in resistance and decrease in rotor thrust; but the balance of torques between the rotor and stator was undisturbed, causing no concern to vehicle roll.

Total Cross Sections for Neutron Nucleus Scattering

Suryanarayana, S.V.,Naik, H.,Ganesan, S.,Kailas, S.,Choudhury, R. K.,Kim, Guinyun Korean Physical Society 2011 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.59 No.2

Nanocrystalline Materials-an Overview

Suryanarayana, C. The Korean Powder Metallurgy Institute 1996 한국분말재료학회지 (KPMI) Vol.3 No.4

Nanocrystalline materials, with a grain size of typically <100 nm, are a new class of materials with properties vastly different from and often superior to those of the conventional coarse-grained materials. These materials can be synthesized by a number of different techniques and the grain size, morphology, and composition can be controlled by controlling the process parameters. In comparison to the coarse-grained materials, nanocrystalline materials show higher strength and hardness, enhanced diffusivity, improved ductility/toughness, reduced, density, reduced elastic modulus, higher electrical resistivity, increased specific heat, higher coefficient of thermal expansion, lower thermal conductivity, and superior soft and hard magnetic properties. Limited quantities of these materials are presently produced and marketed in the US, Canada, and elsewhere. Applications for these materials are being actively explored. The present article discusses the synthesis, structure, thermal stability, properties, and potential application of nanocrystalline materials.

Experimental evaluation of pumpjet propulsor for an axisymmetric body in wind tunnel

Suryanarayana, Ch.,Satyanarayana, B.,Ramji, K.,Saiju, A. The Society of Naval Architects of Korea 2010 International Journal of Naval Architecture and Oc Vol.2 No.1

Design of a Pump Jet Propulsor (PJP) was undertaken for an underwater body with axisymmetric configuration using axial/low compressor design techniques supported by Computational Fluid Dynamics (CFD) analysis for performance prediction. Experimental evaluation of the PJP was earned out through experiments in a Wind Tunnel Facility (WTF) using momentum defect principle for propulsive performance prior to proceeding with extensive experimental evaluation in towing tank and cavitation tunnel. Experiments were particularly conducted with respect to Self Propulsion Point (SPP), residual torque and thrust characteristics over a range of vehicle advance ratio in order to ascertain whether sufficient thrust is developed at the design condition with least possible imbalance torque left out due to residual swirl in the slip stream. Pumpjet and body models were developed for the propulsion tests using Aluminum alloy forged material. Tests were conducted from 0 m/s to 30 m/s at four rotational speeds of the PJP. SPP was determined confirming the thrust development capability of PJP. Estimation of residual torque was carried out at SPP corresponding to speeds of 15, 20 and 25 m/s to examine the effectiveness of the stator. Estimation of thrust and residual torque was also carried out at wind speeds 0 and 6 m/s for PJP RPMs corresponding to self propulsion tests to study the propulsion characteristics during the launch of the vehicle m water where advance ratios are close to Zero. These results are essential to assess the thrust performance at very low advance ratios to accelerate the body and to control the body during initial stages. This technique has turned out to be very useful and economical method for quick assessment of overall performance of the propulsor and generation of exhaustive fluid dynamic data to validate CFD techniques employed.

Consolidation of Nanocrystalline Powders

Suryanarayana, C .,Korth, G . E . 대한금속재료학회(대한금속학회) 1999 METALS AND MATERIALS International Vol.5 No.2

Blended elemental Ti-24Al-11Nb (at.%) and Ti-SSA1 (at.%) powders were mechanically alloyed and consolidated to full density by hot isostatic pressing (HlPing), Ceracon processing, and shock consolidation methods. Nanometer-sized grains were observed in all the samples, the finest size achieved in the shock-consolidated samples. The grain size was larger at higher HIPing temperatures. In comparison with conventional coarse-grained material, the HIP temperature for full consolidation could be brought down by about 400℃ for the nanostructured titanium aluminides.

THE SCIENCE AND TECHNOLOGY OF MECHANICAL ALLOYING

Suryanarayana C. 한국분말야금학회 2000 한국분말야금학회 학술대회논문집 Vol.2000 No.1

Mechanical alloying (MA) is a powder metallurgy processing technique involving cold welding fracturing and rewelding of powder particles in a high-energy ball mill. This has now become an established commercial technique in producing oxide dispersion strengthened (ODS) nickel- and iron-based materials. The technique of MA is also capable of synthesizing non-equilibrium phases such as supersaturated solid solutions metastable crystalline and quasicrystalline intermetallic phases nanostructures and amorphous alloys. In this respect the capabilities of MA are similar to those of another important non-equilibrium processing technique viz rapid quenching of metallic melts. however the science of MA is being investigated only during the past ten years or so. The technique of mechanochemistry on the other hand has had a long history and the materials produced this way have found a number of technological applications e.g. in areas such as hydrogen storage materials heaters gas absorber fertilizers. catalysts cosmetics and waste management. The present talk will concentrate on the basic mechanisms of formation of non-equilibrium phases by the technique of MA and these aspects will be compared with those of rapid quenching of metallic melts. Additionally the variety of technological applications of mechanically alloyed products will be highlighted.

Recent Advances in the Synthesis of Alloy Phases by Mechanical Alloying/Milling

SURYANARAYANA, C 대한금속재료학회(대한금속학회) 1996 METALS AND MATERIALS International Vol.2 No.4

Mechanical alloying (MA) is a solid-state powder processing technique involving repeated welding, fracturing, and rewelding of powder particles in a high-energy ball mill. Originally developed to produce oxidedispersion strengthened nickel- and iron-base superalloys, MA has now been shown to be capable of synthesizing a number of alloy phases - equilibrium and supersaturated solid solutions, stable and metastable crystalline and quasicrystalline intermediate phases, and amorphous alloys. Recent advances in these areas and also on disordering of ordered intermetallics and displacement reactions have been critically reviewed. Wherever possible, comparisons have been made on the product phases obtained by MA and by rapid solidification processing, another non-equilibrium processing technique.

Cavitation studies on axi-symmetric underwater body with pumpjet propulsor in cavitation tunnel

Suryanarayana, Ch.,Satyanarayana, B.,Ramji, K.,Rao, M. Nageswara The Society of Naval Architects of Korea 2010 International Journal of Naval Architecture and Oc Vol.2 No.4

A pumpjet propulsor (PJP) was designed for an underwater body (UWB) with axi-symmetric configuration. Its performance was predicted through CFD study and models were manufactured. The propulsor design was evaluated for its propulsion characteristics through model tests conducted in a Wind Tunnel (WT). In the concluding part of the study, evaluation of the cavitation performance of the pumpjet was undertaken in a cavitation tunnel (CT). In order to assess the cavitation free operation speeds and depths of the body, cavitation tests of the PJP were carried out in behind condition to determine the inception cavitation numbers for rotor, stator and cowl. The model test results obtained were corrected for full scale Reynolds number and subsequently analyzed for cavitation inception speeds at different operating depths. From model tests it was also found that the cavitation inception of the rotor takes place on the tip face side at higher advance ratios and cavitation shifts towards the suction side as the RPS increases whereas the stator and cowl are free from cavitation.

Cavitation studies on axi-symmetric underwater body with pumpjet propulsor in cavitation tunnel

Ch. Suryanarayana,B. Satyanarayana,K. Ramji,M. Nageswara Rao 대한조선학회 2010 International Journal of Naval Architecture and Oc Vol.2 No.4

A pumpjet propulsor (PJP) was designed for an underwater body (UWB) with axi-symmetric configuration. Its performance was predicted through CFD study and models were manufactured. The propulsor design was evaluated for its propulsion characteristics through model tests conducted in a Wind Tunnel (WT). In the concluding part of the study, evaluation of the cavitation performance of the pumpjet was undertaken in a cavitation tunnel (CT). In order to assess the cavitation free operation speeds and depths of the body, cavitation tests of the PJP were carried out in behind condition to determine the inception cavitation numbers for rotor, stator and cowl. The model test results obtained were corrected for full scale Reynolds number and subsequently analyzed for cavitation inception speeds at different operating depths. From model tests it was also found that the cavitation inception of the rotor takes place on the tip face side at higher advance ratios and cavitation shifts towards the suction side as the RPS increases whereas the stator and cowl are free from cavitation.

Performance evaluation of an underwater body and pumpjet by model testing in cavitation tunnel

Ch. Suryanarayana,B. Satyanarayana,K. Ramji 대한조선학회 2010 International Journal of Naval Architecture and Oc Vol.2 No.2

Experimental investigations were carried out on an Axi-symmetric Body Model fitted with Pump-jet Propulsor (PJP) in the Cavitation Tunnel at Naval Science and Technological Laboratory (NSTL). The tests were intended for evaluating the propulsion characteristics of the body and propulsor. The self propulsion point of the model for two configurations was determined after finding the corrections for tunnel blockage effects and differences in model length at zero trim. The results were found to match closely with the towing tank results. The rotor and stator torques also matched closely over full range of experiment. Further experiments were carried out on the body at 4.5º angle of trim to investigate the propulsive performance and assess the operational difficulties in the sea. The results indicated an increase in resistance and decrease in rotor thrust; but the balance of torques between the rotor and stator was undisturbed, causing no concern to vehicle roll. Experimental investigations were carried out on an Axi-symmetric Body Model fitted with Pump-jet Propulsor (PJP) in the Cavitation Tunnel at Naval Science and Technological Laboratory (NSTL). The tests were intended for evaluating the propulsion characteristics of the body and propulsor. The self propulsion point of the model for two configurations was determined after finding the corrections for tunnel blockage effects and differences in model length at zero trim. The results were found to match closely with the towing tank results. The rotor and stator torques also matched closely over full range of experiment. Further experiments were carried out on the body at 4.5º angle of trim to investigate the propulsive performance and assess the operational difficulties in the sea. The results indicated an increase in resistance and decrease in rotor thrust; but the balance of torques between the rotor and stator was undisturbed, causing no concern to vehicle roll.