http://210.212.227.212:8080/xmlui/handle/123456789/62 2026-05-17T00:01:40Z 2026-05-17T00:01:40Z Ashok, K.B Rijo Jacob, Thomas http://210.212.227.212:8080/xmlui/handle/123456789/455 2023-10-07T05:52:29Z 2023-08-29T00:00:00Z

Investigation on the fine tuning of different performance parameters of High Temperature Superconductors Ashok, K.B; Rijo Jacob, Thomas Nuclear fusion can be considered as a viable source of energy in the future when considering the high depletion rate of conventional energy sources and the increase in energy demands. Superconducting magnets being an integral part of any nuclear fusion reactor, wires and cables that can carry a huge amount of current without any loss and with minimum cost are to be developed. The high-temperature superconductors (HTS) are considered to be cost-effective when compared to low-temperature superconductors (LTS). However, the development of HTS-based wires or cables requires much research, mostly because majority of them are brittle. The second-generation HTS of the rare-earth barium copper oxide (REBCO) family are potentially promising because of their large current density and low hysteresis losses. However, being brittle in nature, they must be first transformed into tapes before being converted into superconducting cables and wires for use. REBCO conductors also have many desirable properties required for various applications, such as strength, flexibility, and strain tolerance for winding, and current densities at high to very high magnetic fields even at liquid nitrogen temperatures (77 K). However, they can degrade and lose their superconducting property unless they are kept within certain limits (known as critical limits) in terms of temperature, current density, magnetic field, and structural strain. It is necessary to determine these critical limits for any given type, geometry and size of superconductor when they are subjected to mechanical forces/stresses. HTS tapes and cables being expensive, the experimental investigations for determining these critical limits are costly and also challenging. This is mainly due to their brittle nature, high current density, and cryogenic operating temperatures. Therefore, the use of simulation studies employing FEM software is found to be a viable option. This study, using simulation, attempts to understand the degradation of the REBCO tapes under different mechanical loading (tensile, bending, torsion, cyclic and winding loads) and also by varying the geometric parameters of the tape. The geometry parameters considered are the thickness of the constituting layers (mainly those made of Hastelloy and copper), width of the tape, winding angle, central core diameter, etc. Parametric studies carried out by varying the type and magnitude of the forces applied on them will help to identify the relative involvement of each geometric parameter on performance of the superconducting tape. The model for the simulation studies has been developed using COMSOL Multiphysics and have been compared with the iv experimental and simulation studies reported in the literature. The results are obtained under tension, bending, torsion winding loads and also under the fatigue type of loading. The results obtained reveal that Hastelloy and copper thicknesses have a significant influence on the development of intrinsic strain under tensile and bending loads; but found to be not much significant in the case of torsional load. The tape width is found to be the most crucial parameter in case of torsional loads. By decreasing the tape width, the critical limits can be pushed further, giving more flexibility for the manufacturers to accommodate combined tensile and torsional loads. Decreasing the tape width by 75 %, increased the maximum allowable angle of twist by 326 %. The winding study of simple superconducting CORC cable revealed that 45o is the best angle for winding, and also found that, the intrinsic strain in the REBCO layer is increased with the decrease in the central core diameter. The fatigue loading studiesshowed that the bending load is the most severe one of the three types of loading. Also, it is found that, upon fatigue type loading, the Hastelloy layer fails first, followed by the bottom copper layer, the silver layer, and then the top copper layer for the given tape configuration and loading conditions. It is found that the role of each tape parameter is different depending on the type of load applied. Under the tensile type of load, the thickness of the Hastelloy and copper layers is more significant than other tape parameters. Whereas, under bending, the thickness of the Hastelloy layer has more important role. Under the torsional load, the width of the tape is the most determining parameter. The thickness of the Hastelloy and copper layers is significant in the case of fatigue type of loading for tension, bending and torsion. The various results obtained are expected to help the manufacturers and researchers to develop better HTS REBCO tapes and cables when they are subjected to tension, bending, torsion, cyclic and winding loads as well as under fatigue type of loading

2023-08-29T00:00:00Z Shajan, S Baiju, V http://210.212.227.212:8080/xmlui/handle/123456789/454 2023-10-07T05:49:03Z 2023-03-20T00:00:00Z

Numerical and ExperimenNumerical and Experimental Investigations on the Performance Improvements of Parabolic Trough Solar Thermal Collector for Medium Temperature Applicationstal Investigations on the Performance Improvements of Parabolic Trough Solar Thermal Collector for Medium Temperature Applications Shajan, S; Baiju, V The environmental repercussions of harmful emissions caused by conventional energy fuels such as petroleum and coal are a significant concern in today’s globe. A parabolic trough collector (PTC) is a promising solar energy harvesting technology that provides thermal energy. In conventional PTC receivers, solar fluxes are significantly non-uniform, which can cause high local temperatures and large temperature gradients, posing serious challenges to safety and efficiency. One approach for increasing the service life and dependability of a PTC is to reduce the receiver tube’s circumferential temperature difference that increases with the concentration ratio. This study investigates the design and development of a PTC with a secondary reflector for medium temperature applications and its experimental performances. Tonatiuh, a Monte Carlo ray-tracing based optical simulation tool, is used to obtain the power output and heat flux profiles on the receiver tube surface. Response surface methodology has been used to examine and select the desired configuration of the solar collector system, and the findings have been analysed using ANOVA. The results showed that the uniformity of heat flux distribution has significantly enhanced after the secondary reflector is installed in its most suitable location, compared to the solar collector without the secondary reflector. Therminol® 55 (TH55) oil-based hybrid nanofluids with graphene nanoplatelets and alumina nanoparticles are prepared by two-step method with different concentrations. Compared to the base fluid, the hybrid nanofluid appears to have an 18.72% increase in thermal conductivity at 65°C. A CFD analysis results show that at 0.1 kg/min mass flow rate, the hybrid nanofluids average convection heat transfer coefficient has enhanced by 21.88%. The experimental results revealed that the efficiency of the PTC with the secondary reflector obtained a greater than 6.0 % improvement over conventional PTCs. With a flow rate of 7.5 lpm, the PTC using hybrid nanofluid demonstrated an increase of 4.05 % in average thermal efficiency compared to the PTC using TH55. Overall this study proposes a new design approach of a solar PTC and a new hybrid nanofluid as its heat transfer fluid for efficient operation of PTC systems

2023-03-20T00:00:00Z Asif Sha, A Baiju, V http://210.212.227.212:8080/xmlui/handle/123456789/453 2023-10-07T05:44:32Z 2023-03-10T00:00:00Z

Thermodynamic Modelling and Experimental Investigation of Two Bed Solar Vapour Adsorption Cooling System Asif Sha, A; Baiju, V Adsorption cooling technology is an alternative to conventional cooling systems. The low heat transfer properties of the adsorbent-adsorbate pair utilised in adsorption cooling systems have an impact on the performance of the systems. Thus, researchers are concentrating on enhancing the performance of the system by introducing new composite adsorbent pairs. A transient model of a two-bed adsorption cooling system employing activated carbon-ethanol is presented to evaluate performance. The Coefficient of Performance (COP) and Specific Cooling Power (SCP), have been evaluated using SIMULINK platform. An adsorption chiller of 600 W capacity operating at an evaporator temperature of 50C with isothermal adsorption is used to improve the performance of system. The analysis envisages that a maximum heat input is used for the desorption of adsorbate from the bed and is 4543.44 kJ. The maximum COP is 0.68, for a desorption temperature of 950C. Moreover, the exergy destruction of the adsorbent bed has been evaluated as 0.19 kW. The next phase of the work is the design, development and performance study of the two-bed adsorption cooling system. The evaporator, condenser, adsorbent bed, energy storage tank and solar collector are designed and fabricated. The experimental COP of the system is 0.68 for the maximum hot water inlet temperature of 880C. The study also concentrated to investigate a composite adsorbent for the proposed system. The characteristic study of the composite suggests, composite B, having activated carbon 70% in weight, expanded graphite powder 10%, metal organic framework 10% and binder 10% as the favourable choice for adsorption cooling system. The thermal conductivity of the composite B and volumetric adsorption uptake of activated carbon ethanol is determined as 0.29 Wm-1K -1 and 0.983 respectively. The thermodynamic modelling of the system as well as experimentally with the selected composite adsorbent ethanol is carried out to evaluate its performance. The study reveals that COP of the system increases by 14.81% when using composite as compared with activated carbon-ethanol. The performance of the proposed system with the thermal energy storage material is also investigated. It is observed that the COP of the system increases by 20.69% as compared to the adsorption cooling system that uses activated carbon-ethanol

2023-03-10T00:00:00Z Kavithamol, S Sadiq, A http://210.212.227.212:8080/xmlui/handle/123456789/452 2023-10-07T05:38:06Z 2023-09-01T00:00:00Z

Investigation into soft body impact on laminated composites Kavithamol, S; Sadiq, A The impact of soft bodies such as birds on aircraft structures is a significant threat that leads to serious structural damage and economic loss to the aircraft industry. The leading edges are the foreparts of the aircraft and are always under the possibility of a bird strike. Leading edges are typically fabricated with GLARE laminate, tailored with alternatively arranged aluminium alloy and glass fibre epoxy layers. The approach followed in designing the leading edge is to design it to have a higher energy absorption capacity, thereby transferring less force to the supporting structure. Moreover, the deformation of the leading edge also to be reduced to protect its internal components. The present research aims to improve the bird impact resistance of fibre metal laminates used to fabricate the leading edges. This research is conducted in two parts; the first part is the optimization of the aluminium alloy parameters of the leading edge skin subjected to bird impact. The second part is the analysis of the strength and damage characteristics of different GLARE laminates under soft body impact. For this research, different bird modelling approaches are analysed to establish a soft body model consistent with theoretical and experimental predictions of actual bird strike events. The SPH soft body model with Mie-Grüneisen equation of state parameters exhibited a good correlation with an experimental test based on deformation patterns and pressure distribution characteristics. Then, the soft body impact simulation on the aluminium alloy (AA 2024-T3) wing leading edge is validated with a bird impact experimental test. Soft body impact simulations showed that the material parameters which influence the energy absorbing characterises of aluminium alloys are static yield limit, elastic modulus, strain hardening modulus and hardening exponent. The selected material parameters are optimized and validated with soft body impact analysis on the wing leading edge using Taguchi's L16 design of experiments with grey relational analysis. Quasi-static tension test simulations demonstrate that the mechanical properties of the optimized aluminium alloy are increased 20.84% yield strength, 20% tensile strength, and 25% deformation energy compared to AA 2024-T3. The tension test simulations on different GLARE laminates tailored with optimized aluminium alloy showed an average improvement of 20.87% aluminium alloy yield strength and 20.22% matrix failure strength compared to GLARE laminates tailored with AA 2024-T3. Observations of the soft body impact analysis concluded that the GLARE laminate with the glass/epoxy layers arranged between thinner aluminium alloy layers is most suitable for designing the leading edges.

2023-09-01T00:00:00Z