The gas turbine engine works at very high temperatures above the withstanding capabilities of the materials. Thus, a proper cooling has to be done for various components of the gas turbine engine. The cooling can be done by making secondary flow internal passages throughout the engine for passing the coolant air. These passages are designed without affecting the structure of the gas turbine engine. A computational heat transfer analysis was made by creating various zones on the discs of compressor and turbine. The analysis has been carried out by using ANSYS-FLUENT. Conjugate heat transfer analysis of the complete secondary air path of a gas turbine engine, for incompressible flow with rotation and conjugate heat transfer for the given engine operating conditions was carried out. All the results reported are converged solutions. The results reported are in form of graphical and contour plots. From the results, it was observed that all the necessary flow physics have been captured.
This research fully studied the thermal-mechanical characteristics of aluminium alloy 7475 (AA7475) sheets under hot forming circumstances. The investigation included conducting a variety of isothermal uniaxial tensile experiments at various temperatures and strain rates using an isothermal mechanical simulator, i.e., Gleeble 3500. The Split Hopkinson Tensile Bar (SHTB), a high-velocity testing system, and the electronic universal testing machine were used to conduct dynamic tensile strength tests on AA7475. These tests were conducted to assess the dynamic mechanical behaviour of the alloy at different strain rates. These stress-strain curves were collected at various speeds. The findings signify that the strain rate and hardening impact of AA7475 contribute significantly to the overall impact.
This study focuses on evaluating emission rates and performance attributes of a diesel-powered CI engine run on the blends of Docosahexaenoic acid (DHA) oil biodiesel. The blends used include B10 (DHA biofuel (10%) + diesel (90%)), B20 (DHA biofuel (20%) + diesel (80%)) and B30 (DHA biofuel (30%) + diesel (70%)). The engine’s performance is assessed through Brake Specific Fuel Consumption (BSFC) and Brake Thermal Efficiency (BTE). Emission properties like Nitric Oxide (NOx), Carbon Monoxide (CO), Hydrocarbon (HC), Smoke, Carbon Dioxide (CO2) and Oxygen (O2) are also analysed. Results show a notable decrease in CO, HC, and smoke emissions for DHA biodiesel blends compared to neat diesel, though NOx, CO2, and O2 emissions increase with higher bi-biodiesel content.
A detailed numerical analysis was carried out to study the behaviour of an under-expanded coaxial jet at nozzle pressure ratio of 3. The primary nozzle exit lip thickness considered in this study was 0.7mm, 2.65mm and 4.9mm. Centreline pressure decay, Mach contour and density contour were examined to understand the under-expanded coaxial jet characteristics. The findings demonstrated that the mixing of lip 4.9mm is superior when compared to the other lip thicknesses. The study also found that the core length reduces as the lip thickness is increased. The result also reveals that the shock crossover in the primary core of the under-expanded coaxial jet is strongly influenced by the nozzle lip thickness.
In this study, Graphene Nano Sheets (GNS), Carbon Fiber (CF) and Hemp Fiber (HF) reinforced composites were subjected to tensile and impact tests and their characteristics were optimised using Response Surface Methodology (RSM) and Box-Behnken Design (BBD). A variety of reinforcements were included in the melted Polyethene (PE) using the mix of GNS at 0, 0.9 and 1.8% wt., CF at 0, 9 and 18% wt. and HF at 0, 9 and 18% wt. The greatest Tensile Strength (TS) of 39.84 MPa was attained by a blend of GNS (0.9% wt.), HF (18% wt.) and CF (18% wt.). The TS of the filler doped samples was 52% more than that of pure PE, due to the production of composites with optimal values of each constituent. Impact testing showed that the same optimal combination showed the highest impact strength of 131 J/m, that is 80% more than that of neat PE resin. Using the Scanning Electron Microscope analysis and Fourier-Transform Infrared Spectroscopy, it was found that the mechanical strengths of the GNS doped composites were improved due to the formation of new bonds between polymer chains and the additives.
