The current research was carried out to investigate conventional heat transfer enhancement inside the tube by using twisted stainless-steel angle insert. Main objectives were to find the percentage of increment of heat transfer enhancement using twisted stainless-steel insert and to find the relation between Reynolds number and Nusselt number. A 940mm long copper tube of 26.6 mm internal diameter and 30 mm outer diameter, of which length of 762 mm has been used as the test section. A constant heat flux condition has been maintained by wrapping Nichrome wire around the test section and fiber glass insulation over the wire. K-type thermocouples and rotameter were used to measure temperature and rate of flow. With insert, heat transfer rate has been increased up to 140 percent. This technique does not rely on external power or activation. This experiment has shown simultaneous effects on Reynolds number and Nusselt number too.

Abstract: This study focuses on the numerical simulation of heat transfer and fluid flow within a cooling channel equipped with V-IV ribs. The dimensions of the cooling channel are consistent with those used in experimental investigations to ensure comparability of results. Simulations were conducted using the commercial software STAR CCM+ 2019, modeling three-dimensional, turbulent gas flow under implicit unsteady conditions with wall Y+ considerations. A no-slip velocity condition was enforced at the walls, with a turbulent velocity profile specified at the inlet and a pressure outlet condition at the outlet, maintaining an ambient temperature of 300 K. The Large Eddy Simulation (LES) technique was employed, utilizing high-performance computing resources to achieve timely results. The Wall-Adapting Local Eddy-viscosity (WALE) model was implemented for subgrid-scale turbulence modeling, with first-order temporal discretization and a time step size of 0.0001 seconds. A grid independence study was performed at a Reynolds number of 70,000, using trimmer and surface mesh techniques for mesh generation. Four mesh densities were tested: 2.3 million, 5.6 million, and 8.6 million cells, resulting in Nusselt numbers of 207.68, 228.83, and 228.24, respectively. The 5.6 million cell mesh provided results closely matching the finer mesh configurations and was thus selected for further simulations. The wall Y+ values were analyzed to ensure the effective use of prism layers near the walls, maintaining values below one to resolve the viscous sublayer accurately. Twelve prism layers with a stretching factor of 1.2 were utilized. The velocity distributions were examined for three cases, revealing that the V-IV ribs create secondary flows and recirculation zones, particularly in and after the bend region. This disruption leads to increased turbulence, which is consistently observed across all cases. The study highlights the complex interactions between airflow and rib structures, providing insights into optimizing cooling channel designs for improved heat transfer and fluid flow characteristics.KEYWORDS: Turbulence Modeling, Ribs, Heat Transfer Enhancement, LES, Gas Turbine cooling

This paper represents the components of the Smart Grid, issues regarding the implementation of Smart Grid concept and how battery energy storage systems can be used in the Smart Grid. The relationship between climate change and smart grid, distributed generation and microgrids have been discussed. There is an overview of smart meter, smart tariff, electricity generation, and demand. The battery's potential for Demand Side Management (DSM) has been explained. An extensive review of batteries has been given in terms of their use in the transmission, distribution, and residential sectors. In several segments, the electrical grids of New South Wales (Australia) and California has been discussed as case studies. Finally, some real-world Smart Grid examples have been included.

In 2013, Spain became the first country to implement large-scale solar photovoltaics (SPV) and, in 2018, the first country to have Concentrating Solar Power (CSP), which is the first global CSP accomplishment. In 2018, a cumulative total of about 7,000 MW of solar energy was installed, of which about 5000 MW was solar photovoltaic (PV) and about 2000 MW was concentrated solar power. Main target of this paper is to assess the installation of a 20MW CSP plant in SPAIN and we have found a very positive result. The paper also reviews policies and legislations regarding energy, renewable energy, environment, industry, and climate of SPAIN.

The current research was carried out to investigate blockchain application in power sector. Main objectives were to find the rules, regulations and processes of implementation of blockchain platforms in peer-to-peer transaction and to find a suitable algorithm. Various blockchain platforms have been analyzed and it was found that Ethereum platform is good enough for implementation on peer-to-peer network. Smart Contract, Blockchain Mining, Merkel Tree, Hash Computing Methods, Ring Algorithm, Solidity Language and dApps have been analyzed for implementation. Commercial relations between different traders have been explained. Regulations to control behavior of buyers and sellers have been introduced. Finally, a consensus model has been shown for applying blockchain in peer-to-peer trading market.

Abstract: The internal cooling of gas turbine blades features serpentine channels equipped with various turbulence generators, such as dimples, pin-fins, and ribs. These generators are critical in reducing surface temperature and enhancing the heat transfer coefficient. Achieving a balance between high heat transfer and low-pressure drop remains a significant challenge. While offering superior heat transfer, pin-fins result in a high-pressure drop, whereas dimples have gained popularity due to their optimal heat transfer and pressure drop balance. This study focuses on the rotational effects of gas turbine blade internal cooling using dimples, providing insights into the density and buoyancy effects within the cooling channel. Two types of dimples—partial spherical and leaf dimples—were examined experimentally and numerically. Experiments were conducted with a heat flux range of 1,300 to 40,000 W/m2 and a Reynolds number of 50,000, utilizing an experimental setup capable of rotating up to 1,000 rpm, with tests completed at 900 rpm. The Large Eddy Simulation (LES) technique was employed for numerical analysis. The investigation revealed the influence of buoyancy forces on the heat transfer coefficient within a cooling channel with an aspect ratio of 1:1. Results indicated that the leaf-dimpled channel provided superior heat transfer enhancement compared to the partially spherical dimpled channel.KEYWORDS: Gas Turbine Blade, Internal Cooling Channel, Rotational Experimental Setup, Pin-fins, Large Eddy Simulation, Thermal PerformanceNomenclature

Abstract:The internal cooling passage of turbine blades represents one of the most complex zones within a gas turbine system, primarily due to the extreme temperatures encountered in this region. Pin-fins offer a highly effective solution for enhancing cooling efficiency in these passages by significantly increasing the heat transfer coefficient. Additionally, pin-fins provide structural support by bridging the turbine blades’ thin metallic pressure and suction surfaces. However, the implementation of pin-fin cooling is associated with a considerable increase in pressure drop, which can adversely affect the thermal performance of the cooling channel. This study aims to optimize pin-fin design to achieve an optimal balance between heat transfer enhancement and pressure drop. Two distinct pin-fin designs, namely partial spherical and dome-shaped, were evaluated in various array configurations. Both experimental and computational investigations were conducted. Experimental studies were performed with Reynolds (Re) numbers ranging from 9,000 to 50,000, while computational simulations employed the Large Eddy Simulation (LES) technique, covering rotation numbers (Ro) from 0 to 0.13. The evaluation criteria included the heat transfer coefficient, friction factor, and overall thermal performance of the cooling channel. Results indicate that the cooling channel equipped with dome-shaped pin-fins arranged in a 14×2 array configuration exhibited superior thermal performance compared to other designs. This optimization demonstrates the potential for significant improvements in the thermal management of gas turbine blades through careful design and arrangement of pin-fins..KEYWORDS: Gas Turbine Blade, Gas Turbine Blade, Internal Cooling Channel, Rotational Experimental Set-up, Pin-fins, Large Eddy Simulation, Thermal Performance.Nomenclature

Abstract: This study investigates the potential of transpiration cooling for high-temperature applications utilizing a sintered porous flat plate (100 µm porosity) with dry air as the coolant. The investigation focuses on how the plate material coolant flow rate and thermal conductivity influence surface temperature distribution. Findings demonstrate that even minimal coolant injection significantly reduces heat transfer, thereby enhancing the protective capabilities of the system. Cooling Effectiveness increases with higher flow rates, suggesting an optimal range where the cooling performance is maximized. However, the benefits diminish at higher injection levels due to the onset of diminishing returns, wherein increased coolant usage does not proportionally reduce the surface temperature. Furthermore, the study examines the pressure drop across the porous media and its correlation to the coolant Reynolds number, which varied from 47000 to 64000. This relationship provides vital insights into the design constraints of such cooling systems. A relationship between the pressure drops and the Reynolds number is characterized, offering critical data for optimizing system efficiency. Key parameters such as coolant flow rate, thermal conductivity of the material, pressure drop, and friction factor are pivotal in enhancing the transpiration cooling system efficiency and effectiveness for high-temperature operations. The study elucidates an intricate balance required between coolant flow characteristics and thermal management, contributing to the optimization of transpiration cooling technologies.KEYWORDS: transpiration cooling, porous media, cooling effectiveness, thermal performance