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D. Sandanasamy ¹, S. Govindarajane ², T. Sundararajan ³

Affiliations
1 Principal, Karaikal Polytechnic College, Karaikal and Ph.D. Research Scholar, Civil Engineering Department, Pondicherry Engineering College, Puducherry, IN
2 Associate Professor, Department of Civil Engineering, Pondicherry Engineering College, Puducherry, IN
3 Professor, Department of Civil Engineering, Pondicherry Engineering College, Puducherry, IN

Abstract

Enormous amount of energy is radiated from the sun. The electromagnetic waves emitted from the sun have three components namely i) ultra visible (UV), ii) visible (visible to human eye) and iii) solar infrared (near). The solar infrared waves transfer its energy in the form of heat to the object/building when it comes in contact with them. This solar energy is used for producing electricity, heating water, and cooling purpose etc. Hence scientists and engineers have focused their attention to invent new technologies for the effective use of solar energy. This paper highlights the use of solar energy in cooling systems. It is estimated that the demand for air-conditioning units has increased from about 25 million units (MU) in 1998 to more than 40 MU in 2006. The above demand has contributed to higher consumption of electricity and consequently to green house gas (GHG) emissions and global warming. This paper narrates the alternate method, of using solar energy for driving cooling systems in green buildings. It has been suggested to create awareness among consumers and engineers to divert their attention towards solar-assisted cooling systems for new invention and mass production with a view to reduce the unit price. The needs to encourage the research in India, especially for inventing affordable, small solar assisting air-conditioning systems in the near future, have also been emphasized. As a case study, the various data available in rural region of Karaikal were collected and analyzed to show the use of sun energy for cooling system for housing are also highlighted.

Keywords

Solar Energy, Closed Systems, Open Systems, Green Buildings

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R. Venkatraman ¹, S. Sankaran ¹, S. V. Subba Rao ¹, P. Krishnaiah ², T. Sundararajan ³

Affiliations
1 Satish Dhawan Space Centre, Sriharikota-524124, IN
2 Sri Venkateswara Univeristy, Tirupathi, IN
3 Department of Mechanical Engineering, IIT Madras, IN

Abstract

Several transient events occur during the startup of the Solid Rocket Motor (SRM) during the launch vehicle lift-off. Each event produces a complex transient signal and requires systematic assessment. The event discussed in this paper is Ignition Over Pressure (IOP). This Ignition Over Pressure is resulting from fluid dynamic compression of the accelerating plume gas, subsequent rarefaction and propagation during the pressure rise rate period in the rocket combustion chamber. These high-amplitude unsteady fluid-dynamic perturbations can adversely affect the vehicle and its surrounding structure. This wave behaves as a blast or shock wave characterized by a positive triangular shaped first pulse and negative half sine wave second pulse. The pulse travels upwards towards the propulsion system and has the potential to overload the individual elements or exciting overall vehicle dynamics. The later effect results from the phase difference of the wave from one side of the vehicle to the other due to the skew in the ignition of the strap-on boosters. In the case of the launchers, the mechanical stress due to the ignition over pressure wave comes, in addition to the acoustic constraint due to the jet noise. The over pressure phasing or ΔP environment, because of its spectral content as well as amplitudes becomes a crucial input for the design of sub-assemblies viz., thermal shields, and pay loads etc. In this paper, an attempt is made to numerically visualize the propagation of the blast wave causing the unsteady pressure oscillations during the transient pressure rise in the combustion chamber. To understand further, pressure measurements have been made at different heights along the umbilical tower during the solid rocket motor lift-off with the presence of jet deflectors, in order to capture the shock propagation phenomena. From the results, it appears that a sudden shock front that is generated during flow development within the rocket nozzle leaves a clear signature in the form of a well defined peak at typical time intervals. This overpressure amplitude seems to be related to the slope of the combustion chamber pressure rise rate during the transient period. It is also observed that the shock front initially propagates at supersonic speed but decays with time later. Similarly, the magnitude of the IOP peaks are also seen to decay with distance.

Keywords

Ignition Over Pressure, Shock Wave Propagation, Ignition Transient, Solid Rocket Motor, Numerical Flow Visualization

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R. Venkatraman ¹, S. Sankaran ¹, G. Krishnaiah ², P. Malleswara Rao ¹, P. K. Vivekanand ³, T. Sundararajan ³

Affiliations
1 Satish Dhawan Space Centre, Sriharikota-524124, IN
2 Sri Venkateswara Univeristy, Tirupathi, IN
3 Department of Mechanical Engineering, Indian Institute of Technology Madras, Chennai-600 036, IN

Abstract

The Ignition Over Pressure (IOP) is an unsteady pressure wave generated by the ignition of solid rocket motor during launch vehicle lift-off. This wave behaves as a blast or a shock wave followed by a low frequency excitation characterized up to 40 Hz, would cause severe damage to the launch vehicle, its structures and surroundings. However, in case of huge propulsion system, having two solid rocket motors as its boosters, due to the skew in their ignition, during lift-off, the phase difference of the wave from one side of the vehicle to the other could cause a severe moment, which is detrimental to the vehicle. The present paper deals with the occurrence of such blast waves during the testing of various scaled down solid rocket motors. Also, an attempt has been made experimentally to characterize and understand the propagation of the IOP wave causing unsteady pressure oscillations and transient pressure rise in the vicinity of a solid rocket motor. The spectral and directional characteristics of the IOP wave are also highlighted. Typical scaled-down solid rocket motors with and without nozzle shutters have been tested in horizontal firing configuration and the results are compared to study their effect. The resulting shock wave propagation has axial downstream as well as angular directivities. The pressure rise rate in the chamber is found to be directly correlated to the over pressure measured at various locations at the downstream of the nozzle.

Keywords

Directionality, Ignition Over Pressure, Ignition Transient, Shock Wave Propagation, Solid Rocket Motor.

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D. Sandanasamy ¹, S. Govindarajane ², T. Sundararajan ²

Affiliations
1 Karaikal Polytechnic College, Karaikal, IN
2 Department of Civil Engineering, Pondicherry Engineering College, Puducherry, IN

Abstract

India has a large section of rural population, which is deprived of basic amenities like health facilities, drinking water, power and housing facilities etc. Unless rural development takes place, there is no real development of our nation. A speedy development of the rural population will only be able to reduce the disparity between rural and urban people of India and thereby minimize migration of people from rural to urban. Proper technologies have to be selected and properly implemented, to facilitate the speedy development of rural population. This paper suggests the ways in which the rural development can be implemented with sustainability and focuses on issues involved in planning and designing the socio-physical environment in the rural context by ways in which negative intervention with immediate environment can be minimized. As a case study, the various data available in rural region of Karaikal were collected and analysed to show the use of sun energy, natural fibers and construction of rammed walls for rural housing are also highlighted.

Keywords

Green Building, Energy Efficiency, Rural Technology, Sustainable Development, Appropriate Rural Technologies, Case Study.

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D. Sandanasamy ¹, S. Govindarajane ², T. Sundararajan ²

Affiliations
1 Karaikal Polytechnic College, Karaikal, IN
2 Department of Civil Engineering, Pondicherry Engineering College, Puducherry, IN

Abstract

Buildings are responsible for more energy use and CO2 emission, than any other sectors including transportation. Recent efforts world over is to generate energy from renewable resources and thereby save earth from pollution. Building sectors today consumes approximately 45% of total electricity generated in the country. High quality stable energy both electrical and thermal are required to attain the higher growth rate in industry. As fossil fuel are limited and have adverse environmental impact, it would be appropriate to use renewable energy source like biomass resources such as crop residues and agro-industrial wastes for generation of energy for meeting the total energy demand. Biomass materials are used since millennia for meeting myriad human needs including energy. This paper brings out the status of biomass energy, modern technology applied to generate electricity in India. The critical areas such as availability of degraded land for biomass plantation, enhanced biomass producity, economic operations of plantations, logistics infrastructure and efficient conversion for promoting biomass energy for sustainability in green buildings are also projected. This paper highlights the concept “wealth out of waste” by the way of producing electricity from the agro and house hold waste and leaves pollution free environment to the future generation. In the case study, Karaikal town which is a part of United Territory of Puducherry has been considered. Agricultural data and waste produced are calculated which inturn replace the considerable amount of conventional electricity produced by coal/natural gas is also highlighted.

Keywords

Biomass, Electricity, Plantation, Wastes, Case Study.

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P. Maran ¹, T. Somakumar ¹, T. Sundararajan ²

Affiliations
1 Department of Mechanical Engineering, Thiagarajar College of Engineering, Madurai, IN
2 Department of Mechanical Engineering, Indian Institute of Technology, Madras, Chennai, IN

Abstract

Weld pool convection strongly influences the behaviour of molten metal in the melt pool during fusion welding of metals. The temperature and velocity fields in the melt pool are largely affected by different driving forces causing weld pool convection. Variations in the heat input during welding have significant effects on the peak temperature, maximum velocity in the melt pool and weld bead geometry. Buoyancy, electromagnetic and surface tension are the major driving forces. In the present work, the effects of weld pool convection on weld bead geometry of stainless steel during Gas Tungsten Arc (GTA) welding have been studied for individual and combined driving forces. A two dimensional finite volume model has been used to simulate the welding process. The model uses a modified Gaussian heat distribution to provide the three dimensional effect of linear welding.

Keywords

Modeling, Weld Pool, Fluid Flow, GTA Welding, Stainless Steel, Weld Bead Geometry.

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P. Maran ¹, T. Sornakumar ¹, T. Sundararajan ²

Affiliations
1 Department of Mechanical Engineering, Thiagarajar College of Engineering, Madurai-625015, IN
2 Department of Mechanical Engineering, Indian Institute of Technology, Madras, Chennai-600036, IN

Abstract

The experimental studies on microstructures and micro hardness in the weld metal show that the fluid flow pattern in the weld pool strongly influences the cooling rate, microstructure and hardness. The fluid pattern predicted is correlated with the experimental results for microstructures and hardness. The spatial variations of micro hardness show that the micro hardness values are higher in the low velocity fluid flow region and lower in the remaining region. The variations are due to different cooling rates, micro structures, sizes of the grains and delta ferrite content.

Keywords

Modeling, Weld Pool, Fluid Flow, Weld Bead Geometry, Microstructure, Micro Hardness.

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