The higher firing temperature reflects the higher efficiency of the gas turbine. However, using higher temperatures is limited as it may cause a rupture, bending, or failure of the turbine blades. Hence, the development of an effective internal cooling system of the gas turbine blade is essential. At the same time, it is necessary to ensure the lowest possible penalty on the thermodynamics performance cycle. To find out the better cooling channel design with high heat transfer while the lowest pressure drop, researchers are working over the years both experimentally and numerically. This study reviews the overall internal cooling, such as using rib turbulators, dimples, jet impingement, pin fins, guide vane, etc. of the gas turbine blade.
Air compressors, a key fluid power technology, play an important role not only in industrial plants but also in office buildings, hospitals, and other types of facilities. The efficient use of the air compressor is crucial to control unnecessary inefficiencies that cause high energy consumption. This study aims to provide energy and exergy analysis on air compressors for different industries. Detailed case studies are also analyzed. The case study focuses on the energy and exergy analysis of the compressed air system of foundry industries. The results indicate that applying the six improvement recommendations yield significant amounts of energy and cost savings as well as significant improvements in the overall performance of the system. The payback periods for different recommendations are economically feasible and worthwhile to use. The suggested improvement methods can provide high costs with a low payback period.
This study presents an analytical method that can be used to enhance the power production rate and the energy-saving at wastewater treatment plants. The digester used at wastewater treatment plants produce digester gas by anaerobic digestion, with which biofuel production can be achieved. Biofuels can be used to meet some of the energy requirements of the wastewater treatment facility through Combined Heat and Power (CHP) gas engines (co-generation). Using Micro Gas Turbine (MGT), a CHP technology can be introduced in Wastewater Treatment Plants (WWTPs). The combination of MGTs and absorption chillers is a promising technology as it produces electricity, heating, and cooling simultaneously. The study demonstrated how the waste heat of MGTs could be used to drive absorption chillers. In this analytical study, a detailed technical and economic analysis is provided on the tri-generation system, i.e., the integration of MGTs and absorption chillers driven by waste digester gas of the wastewater treatment plants. It can meet the heating and cooling demands of the plants, which promote the reduction of utility costs. The technology presented is also useful for other thermal energy users.
The primary objective of this study is to achieve net-zero-energy (NZE) wastewater treatment plants (WWTPs) by utilizing energy efficiency opportunities (EEO's), combined heat and power (CHP) systems, and other renewable energy sources, e.g., solar, water, and wind powers. This study discusses an innovative energy solution for WWTPs in the United States, and one of the WWTPs with a flow capacity of 1.5 million gallons per day (MGD) was selected as a case study. An optimization tool, Hybrid Optimization of Multiple Energy Resources (HOMER) software, is used in this study to find the best energy system configuration to run the system. An energy audit for one WWTP in early 2020 and the report is used to do this study. The proposed EEO's were able to reduce WWTP energy consumption by about 11%. The excess anaerobic digester gas was utilized in a CHP system to cover about 42% of the facility's consumption. Also, 3% of the utility energy consumption can be claimed by microturbines in the aeration tanks. Another two renewable energy systems, solar photovoltaic (PV) with 29% and water turbines with 15%, contribute to covering 100% of the WWTP energy consumption and achieving an NZE WWTP.
Internal cooling of gas turbine blades is performed with the combination of impingement cooling and serpentine channels. Besides gas turbine blades, the other turbine components such as turbine guide vanes, rotor disks, and combustor wall can be cooled using jet impingement cooling. This study is focused on jet impingement cooling, in order to optimize the coolant flow, and provide the maximum amount of cooling using the minimum amount of coolant. The study compares between different nozzle configurations (In-line and staggered), two different Reynold's numbers (1500 and 2000), and different stand-off distances (Z/D) both experimentally and numerically. The stand-off distances (Z/D) considered are 3, 5, and 8 In jet impingement cooling, the jet of fluid strikes perpendicular to the target surface to be cooled with high velocity to dissipate the heat. The target surface is heated up by a DC power source. The experimental results are obtained by means of thermal image processing of the captured Infra-Red (IR) thermal images of the target surface. Computational fluid dynamics (CFD) analysis were employed to predict the complex heat transfer and flow phenomena, primarily the line-averaged and area-averaged Nusselt number and the cross-flow effects. In the current investigation, the flow is confined along with the nozzle plate and two parallel surfaces forming a bi-directional channel (bi-directional exit). The results show a comparison between heat transfer enhancement with in-line and staggered nozzle arrays. It is observed that the peaks of the line averaged Nusselt Number (Nu) become less as the stand-off distance (Z/D) increases. It is also observed that the fluctuations in the stagnation heat transfer are caused by the impingement of the primary vortices originating from the jet nozzle exit.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.