Error Estimation of Measured Exhaust Gas Temperature in Afterburner Mode in an Aero Gas Turbine Engine

In a turbofan engine, thrust is a key parameter which is measured or estimated from various parameters acquired during engine testing in an engine testbed. Exhaust Gas Temperature (EGT) is the most critical parameter used for thrust calculation. This work presents a novel way to measure and correct the errors in EGT measurement. A temperature probe is designed to measure EGT in the engine jet pipe using thermocouples. The temperature probe is designed to withstand the mechanical and temperature loads during the operation. Structural analysis at the design stage provided a strength margin of 90% and eigenfrequency margin of more than 20%. Thermal analysis is carried out to evaluate maximum metal temperature. Errors are quite high in high-temperature measurements which are corrected using the available methodologies. The velocity error, conduction error, and radiation error are estimated for the measured temperature. The difference of 97 K between the measured gas temperature and calculated gas temperature from measured thrust is explained. The estimated velocity error is 1 K, conduction error is 3 K, and radiation error is 69 K. Based on the error estimation, the measurement error is brought down to 24 K. After applying the above corrections, the further difference of 24 K between measured and estimated value can be attributed to thermocouple error of +/-0.4% of the reading for class 1 accuracy thermocouple, other parameter measurement errors, and analysis uncertainties. The present work enables the designer to calculate the errors in high-temperature measurement in a turbofan engine

Finite Element Analysis of Squirrel Cage Ball Bearingsfor Gas Turbine Engines

Squirrel cage ball bearings are used in recent aero engines to overcome the vibration andstability problems associated with rotor systems supported by conventional bearings. The criticaldesign feature of squirrel cage bearing is to provide flexible support to rotor system. The outerring of the bearing is configured such that it acts as a flexible bearing support, and hence, weightis minimised. The bearing is mounted directly on a rigid intermediate casing of a gas turbineengine. Finite element analysis helps to obtain a suitable geometry at the design stage. A 3-Dmodel of the bearing is created using IDEAS software. Finite element analysis using contactelement has been carried out for finding the deformation and stresses in the webs at variouslocations using ANSYS software. The deformations are compared with those of experimentalvalues for an axial load. The deformation in the webs is used to check the pressure balance inthe compressor and the load acting on the bearing. Finally, a procedure for doing the finiteelement analysis of ball bearings for combined axial and radial load is laid down

Angel Child : Foxtrot Song

https://digitalcommons.library.umaine.edu/mmb-vp/1005/thumbnail.jp

Nirmal Gram Puraskar: A Unique Experiment in Incentivising Sanitation Coverage

Abstract Clean drinking water and proper sanitation facilities are indispensable for a healthy life

Multiple Bifurcation Types and the Linear Dynamics of Ion Sputtered Surfaces

We study the patterns formed on ion sputtered Si surfaces as a function of ion energy and incidence angle, and identify a region in parameter space where the flat surface is stable. The boundaries between the stable and pattern-forming regions represent mathematical bifurcations. Our data set exhibits at least two different bifurcation types. We discuss the constraints imposed by these observations on the correct model of long wavelength dynamics of ion sputtered surfaces.Engineering and Applied Science

Evaluation of the Status of the Kemp\u27s Ridley Sea Turtle After the 2010 Deepwater Horizon Oil Spill

Coincident with the 2010 Deepwater Horizon oil spill, unprecedented numbers of Kemp’s ridley sea turtles (Lepidochelys kempii) stranded on northern Gulf of Mexico beaches and the number of nests recorded on the primary nesting beaches plummeted far below expected levels. High levels of strandings have continued since 2010 and the number of nests recovered to approximately 2009 levels in 2011, and improved slightly in 2012. A stock assessment conducted in 2012 indicated that a mortality event occurred in 2010, and that the number of nests should once more exhibit an increasing trend from 2013 and beyond. This has not happened; rather, the number of nests declined sharply in 2013. We conducted a new stock assessment to evaluate additional scenarios, including 1) three stock-recruitment options; 2) the potential that a new source of ongoing mortality is present; and 3) the potential that the number of nests-per-adult-female is dependent on the size of the age-2+ benthic population. The latter model provided the best fit to the data. Further, the preliminary estimate of actual nesting in 2014 is consistent with model projections. The reduction in reproductive output could be due to the combination of a large population and reduced prey levels. Together these may have increased the remigration interval or reduced the number of nests per female. However, research is needed to evaluate this and other plausible hypotheses. Nesting may be highly variable in the future depending on feeding conditions on the foraging grounds

The BAT AGN Spectroscopic Survey -- XVIII. Searching for Supermassive Black Hole Binaries in the X-rays

Theory predicts that a supermassive black hole binary (SMBHB) could be observed as a luminous active galactic nucleus (AGN) that periodically varies on the order of its orbital timescale. In X-rays, periodic variations could be caused by mechanisms including relativistic Doppler boosting and shocks. Here we present the first systematic search for periodic AGNs using $941$ hard X-ray light curves (14-195 keV) from the first 105 months of the Swift Burst Alert Telescope (BAT) survey (2004-2013). We do not find evidence for periodic AGNs in Swift-BAT, including the previously reported SMBHB candidate MCG+11$-$11$-$032. We find that the null detection is consistent with the combination of the upper-limit binary population in AGNs in our adopted model, their expected periodic variability amplitudes, and the BAT survey characteristics. We have also investigated the detectability of SMBHBs against normal AGN X-ray variability in the context of the eROSITA survey. Under our assumptions of a binary population and the periodic signals they produce which have long periods of hundreds of days, up to $13$% true periodic binaries can be robustly distinguished from normal variable AGNs with the ideal uniform sampling. However, we demonstrate that realistic eROSITA sampling is likely to be insensitive to long-period binaries because longer observing gaps reduce their detectability. In contrast, large observing gaps do not diminish the prospect of detecting binaries of short, few-day periods, as 19% can be successfully recovered, the vast majority of which can be identified by the first half of the survey.Comment: 17 pages, including 8 figures and 4 tables. Accepted for publication in Ap

Rendimiento, rentabilidad y eficiencia agronómica de nitrógeno en maíz de secano con fertilización foliar complementaria de Zn y Mo

El objetivo de la investigación fue evaluar el efecto de aplicaciones foliares complementarias de Zn y Mo sobre el rendimiento, rentabilidad y eficiencia agronómica del nitrógeno en maíz de secano. El trabajo se desarrolló durante las temporadas lluviosas 2020 y 2021, en el valle del río Carrizal, Manabí, Ecuador. Los tratamientos evaluados fueron: Fertilización edáfica NPK complementada con aplicación foliar de Zn y Mo (T1), y fertilización edáfica NPK sin aplicación foliar de Zn y Mo (T2). Se registró el rendimiento de grano (RG), eficiencia agronómica de N (EAN) y el beneficio económico neto de la fertilización (BEN). Los datos fueron analizados con prueba estadística de t de Student para observaciones pareadas. El tratamiento T1 aumentó el RG en 15,58% y 14,03% durante el 2020 y 2021, respectivamente, con respeto al tratamiento T2. Del mismo modo, el tratamiento T1 incrementó la EAN en un 28,30% y 24,60%, en las temporadas 2020 y 2021, respectivamente, con respeto al tratamiento T2. Finalmente, el tratamiento T1 produjo el mayor BEN, con un incremento del 23,05% y 16,37%, durante el 2020 y 2021, respectivamente, con relación al tratamiento T2. La fertilización foliar complementaria con Zn y Mo, potenció el efecto de la fertilización edáfica NPK e incrementó el rendimiento, rentabilidad y EAN en maíz de secano