Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
Results
Showing 1 to 16 of 16 for “"u-bend"”.
-
Adjoint-based optimization of U-bend channel flow using a multi-fidelity eddy viscosity turbulence model
… thesis presents CFD simulation of a 180 degree U-bend square duct using low-fidelity steady RANS and high-fidelity wall-resolved Large Eddy Simulation (LES) models. The LES solution is shown to match experimental results, whereas the RANS solution is not sufficiently accurate. A process for …
-
The effect of nitrogen content on the susceptibility to stress-corrosion cracking of type 20Cr-20Ni and AISI type 310 stainless steels
… cracking were studied by exposing the U-bend specimens of the alloys containing various nitrogen levels to magnesium chloride solutions boiling at 154°C. It was found that the increase in nitrogen levels up to 0.161 wt.% did not induce cracking in type 20Cr-20Ni alloys even after long …
-
Numerical investigation of the fluidelastic instability of two-phase flow in a parallel triangular tube array
… yet the phenomenon is not well understood. The U-bend region of the steam generator is very prone to the FEI and the flow in this region is characterized by a two-phase nature. Most studies of this phenomenon have been carried out experimentally on specific tube arrays at certain conditions, and …
-
Investigation of Chloride-induced Stress Corrosion Cracking for Long-Term Storage of Spent Nuclear Fuel in Dry Storage Systems
… to examine 304 and 304L stainless steel U-bend and welded U-bend samples. The samples were exposed to chloride rich and humid fogging in a corrosion chamber at 35℃ continuously for 4 weeks, 8 weeks, and 12 weeks. The same experiment was repeated at 50℃ for 4 weeks, 8 weeks, and 14 weeks to …
-
Wall Modeled Large-Eddy Simulations in Rotating Systems for Applications to Turbine Blade Internal Cooling
… _b = 49,000, and two-pass smooth duct with a U-bend at ã Reã _b = 25,000 for ã Roã _b = 0 to 0.238 against WRLES and experimental data. In addition, for the two-pass smooth duct with a U-bend simulations, the synthetic eddy method (SEM) is used to artificially generate eddies at the inlet based …
-
Effect of pre-exposure thermal treatment on susceptibility of type 304 austenitic stainless steel to stress corrosion
… nucleation and rate of crack propagation. U-bend specimens were exposed to 42 weight percent magnesium chloride aqueous solution after pre-exposure heat treatments at 140°C and 154°C. The straight-line relationship between maximum crack depth and the logarithm of exposure time expressed by …
-
Evaluation of susceptibility of AISI 304 to stress-corrosion cracking in terms of crack nucleation and crack propagation
… nucleation and rate of crack propagation. U-bend specimens were exposed to magnesium chloride solutions boiling at atmospheric pressure for some predetermined time. The concentrations of magnesium chloride employed were 40, 42, and 44 per cent by weight. After exposure, specimens were …
-
Evaluation of local heat transfer and friction factors in a U-type compound parabolic collector operating as a thermosyphon
… flows at the inlet, outlet, and through multiple bends. Therefore, this study aimed to determine the heat transfer coefficients and friction factors in an XCPC absorber tube operating as a thermosyphon. The local Nusselt numbers and local friction factors were obtained numerically. It was found …
-
The Effect of Lead on Dealloying and Stress Corrosion Cracking (SCC) of Ni-Cr-Fe Alloys in Boiling Caustic Environments
… and subtle changes in Ni content. Twisted and U-bend samples of SS 304L were used to evaluate the effect of stress on dealloying and SCC. All exposed surfaces were characterized post-exposure using optical microscopy, scanning electron microscopy (SEM), and energy dispersive x-ray spectroscopy …
-
Polymer-Derived Ceramic Coatings for Stress and Corrosion Resistance in Stainless Steel: Optimization of Thermal Stability and Structural Integrity
… were anlayzed for their performance on U-bend stainless steel specimens. Coatings pyrolyzed at lower temperatures exhibited superior SCC resistance due to their flexible and defect-resistant structure, while higher-temperature coatings, despite their improved hardness, were prone to …
-
Detailed Experimental Measurements of Heat Transfer Augmentation in Internal Channels Using a Thermochromic Liquid Crystal Technique
… provide insight into replacing a traditional U-bend channel in a turbine blade.
-
A Study of Immersed Boundary Method in a Ribbed Duct for the Internal Cooling of Turbine Blades
… flow in a developing staggered ribbed U-bend duct. Three cases have been tested at a bulk Reynolds number of 10⁵: a stationary case; a positive rotation case at a rotation number Ro=0.2; and a negative rotation case at Ro=-0.2. Coriolis force effects are included in the calculation to …
-
Influence of heat treatment condition on the stress corrosion cracking properties of low pressure turbine blade steel FV520B
… heat treatment conditions was quantified using U-bend specimens while crack growth rates and threshold stress intensities for SCC (KISCC) were measured using fatigue precracked wedge open loaded (WOL) specimens. Both SCC tests were conducted in a 3.5% NaCl environment maintained at 90°C. XRD …
-
Influence of the heat treatment procedure on the stress corrosion cracking behaviour of low pressure turbine blade material FV566
… The first set of tests was carried out with U-bend specimens to determine the susceptibility of materials at different heat treatments to SCC, the time taken for SCC to initiate, and the mode of cracking. The second set of tests was conducted to determine the threshold stress intensity, as a …
-
Photobioreactor Design for Improved Energy Efficiency of Microalgae Production
… bottom by standard 90-degree PVC elbows in a U-bend fashion to each column to make a total working volume of 235 L. The airlift columns were about 1.5 m tall and 30.5 cm ID, while the serpentine tubes were about 0.9 m tall and 7.6 cm ID to make a total of five vertical tubes for every airlift …
-
An Analysis of Microstructure and Corrosion Resistance in Underwater Friction Stir Welded 304L Stainless Steel
… to base metal and arc weldments was performed. U-bends were exposed to two 3.5% NaCl cyclic immersion experiments at 21 °C and 63 °C for 1000 hours each. A tertiary test was conducted in a 25% NaCl boiling solution. The UWFSW u-bends were no more susceptible to SCC than base metal in the cyclic …