scholarly journals Comparative Study of a Powerplant Life Consumption Rate When Installed in Two Different Aircraft Variants

Aerospace ◽  
2021 ◽  
Vol 8 (11) ◽  
pp. 327
Author(s):  
Ioannis Templalexis ◽  
Ioannis Lionis ◽  
Nikolaos Christou
Keyword(s):  
Air Force ◽  
Consumption Rate ◽  
Low Cycle Fatigue ◽  
Rotor Blades ◽  
Parameter Method ◽  
Great Level ◽  
Consumption Rates ◽  
Life Consumption ◽  
Mission Profile ◽  
Engine Life

The Hellenic Air Force (HAF) operates both EMB-145 and EMB-135 LR versions of Embraer aircraft, used in surveillance and civil missions respectively. These aircraft are equipped with the same version of Rolls Royce, AE 3007 turbofan engine. This study aims to quantify and compare the life consumption rate of this engine when installed in each of the two aircraft variants. Two typical missions, one for each variant, were constructed based on mission profile data dictated by the aircraft commanders. For each mission profile segment, corresponding engine data were matched out of the engine recordings archives held by the Hellenic Air Force. The life consumption rate was based on the Low Cycle Fatigue (LCF) and creep cumulative detrimental effect on the rotor blades of the 1st High-Pressure Turbine stage. For the LCF, the rainflow method was used to determine the respective loading cycles, whereas the Larson - Miller parameter method was used to determine the consumed life fractions due to creep. The main conclusion of the study was that the engine when installed in the EMB-145 military variant, is much more loaded. Despite the fact absolute life consumption values could hide a great level of uncertainty, the comparative outcomes wherein errors are, to a certain extent, cancelled out, could be used as a rule of thumb when monitoring engine life consumption rates.

Turboprop Engine Loading During High and Low Maneuver Intensity Flight Mode

2021 ◽  
Author(s):  
Ioannis Templalexis ◽  
Lambros Giachalis ◽  
Ioannis Lionis
Keyword(s):  
Consumption Rate ◽  
Low Cycle Fatigue ◽  
Management Plan ◽  
Simulation Software ◽  
Time Data ◽  
Gas Generator ◽  
Loading Mode ◽  
Turboprop Engine ◽  
Life Consumption ◽  
Engine Life

Abstract The life consumption rate of the aircraft engine is a vital input for aircraft operators who aim to an efficient fleet management. T6 aircraft, propelled by the PT6 turboprop engine, is operated by the Hellenic Air Force, both for training and aerobatic purposes. The current study focuses on quantifying and comparatively assessing the engine life consumption rate for the following missions: i) An “aerobatic” mission which is a typical high intensity maneuver flight and ii) a “training for patrol” mission, representing a typical low intensity maneuver flight. Missions were selected with the criterion of setting the lowest and the highest possible engine loading during a certain mission. In other words, the goal of the study is to define the extent of the loading the engine can encounter as a propulsion system of the T-6 aircraft during a certain mission. This is the first step before proceeding in setting up a methodology for continuously monitoring the engine life consumption rate in support of the squadron flight management plan. The study was based on real time data recorded during the respective flights. An engine model built using “GasTurb” gas turbine simulation software was used to fill in engine operating data at stations where recordings have not been taken. Engine life consumption was based on creep and low cycle fatigue failure mechanisms of the first gas generator turbine stage. Creep life fractions were calculated based on the Larson-Miller parameter curves and the fatigue cycles were counted using the rainflow method. The study showed that the life consumption is about 10 times lower when the aircraft is operated at a low loading mode as opposed to a high loading mode.

Implications of Turbine Erosion for an Aero-Engine’s High-Pressure-Turbine Blade’s Low-Cycle-Fatigue Life-Consumption

2009 ◽  
Vol 131 (5) ◽  
Author(s):  
Muhammad Naeem
Keyword(s):  
High Pressure ◽  
Fatigue Life ◽  
Low Cycle Fatigue ◽  
Life Cycle Costs ◽  
Cycle Fatigue ◽  
Mechanical Device ◽  
High Pressure Turbine ◽  
Aero Engine ◽  
Life Consumption ◽  
Mission Profile

Some in-service deterioration in any mechanical device, such as a military aero-engine, is inevitable. As a result of experiencing any deterioration, an aero-engine will seek a different steady operating point thereby resulting in a variation in the high-pressure spool speeds in order to provide the same thrust to keep aircraft’s performance invariant. Any increase in the high-pressure spool speed results in greater low-cycle fatigue damage for the hot-end components and thereby higher engine’s life-cycle costs. Possessing better knowledge (of the impacts of high-pressure turbine’s erosion upon the low-cycle fatigue life-consumption of aero-engine’s hot-end components) helps the users to take wiser management decisions. For a military aircraft’s mission profile, using bespoke computer simulations, the impacts of turbine erosion for high-pressure turbine-blade’s low-cycle fatigue life-consumption have been predicted.

Correlation Between Engine and Aircraft Loadings for Several Mission Types

2020 ◽  
Author(s):  
Ioannis Templalexis ◽  
Ioannis Lionis ◽  
Sotiris Kitinos
Keyword(s):  
Structural Integrity ◽  
Low Cycle Fatigue ◽  
Structural Condition ◽  
Daily Basis ◽  
Time Data ◽  
Time Step ◽  
Turbine Engine ◽  
Statistical Measures ◽  
Life Consumption ◽  
Engine Life

Abstract Fighter aircraft constitutes a well-defined class of aircraft. Their extensive use on a daily basis by operators stands as a strong motive behind studies that concern their rate of “exhaustion ”. For an aircraft operator either civil or military, it is very important at any point in time to have a clear view of the engines’ and the aircrafts’ operating condition. This is valuable information in order to foresee undesired incidences and in order to schedule missions in accordance to the actual and anticipated maintenance needs. For the latter, the operator would also need to know the rate of the engine and the aircraft life consumption per mission. The current study concerns the F-16 Block 52M aircraft, powered by the Pratt and Whitney F100-PW-229 engine. Aircraft is continuously subjected to crack growth mechanisms while flying. On the other hand, engines also go through Low Cycle Fatigue (LCF) cycles and creep prominent conditions while being in operation. The engine and the aircraft structural condition are continuously monitored, based on real time data recordings. To the extent of the authors’ knowledge, that is a common practice for most F-16 users. However, what was found to be missing from the international literature was a study to quantify any potential correlation between the aircraft loading and the engine loading for all typical mission types an aircraft of this type undertakes. For users that have already installed an aircraft loading monitoring system like “Aircraft Structural Integrity Program” (ASIP) it would be very useful to set a “rule of thumb” aside regarding the degree of correlation between aircraft and engine loading. Engine life consumption rate was estimated based on the creep and LCF failure mechanisms applied on the most critical engine section, the turbine. Engine recordings were picked from an arbitrary sample of 200 flights of a certain aircraft, wherein most typical mission types could be found. Turbine and subsequently blade temperature as well as blade stress were calculated using a very narrow time step. These data along with blade material data were fed in the Larson Miller model, to set an algorithm for estimating life consumption due to creep. Engine Total Accumulated Cycles (TACs) which account for LCF loading, are directly measured by the engine recorder, based on an embedded algorithm. Aircraft loading is calculated based on the accelerations the aircraft structures encounter during flight. These are also recorded under a very narrow time step. Last step was the correlation of the engine life consumption against the aircrafts’ loading for typical mission types. Scatter diagrams and statistical measures were used, in order to define the degree of correlation between them.

Estimating oxygen consumption rates of arteriolar walls under physiological conditions in rat skeletal muscle

2005 ◽  
Vol 289 (1) ◽  
pp. H295-H300 ◽  
Author(s):  
Masahiro Shibata ◽  
Shigeru Ichioka ◽  
Akira Kamiya
Keyword(s):  
Vascular Tone ◽  
Consumption Rate ◽  
Vascular Wall ◽  
Surrounding Tissue ◽  
Phosphorescence Quenching ◽  
Physiological Conditions ◽  
First Order ◽  
Vascular Walls ◽  
Consumption Rates

To examine the effects of vascular tone reduction on O2 consumption of the vascular wall, we determined the O2 consumption rates of arteriolar walls under normal conditions and during vasodilation induced by topical application of papaverine. A phosphorescence quenching technique was used to quantify intra- and perivascular Po2 in rat cremaster arterioles with different branching orders. Then, the measured radial Po2 gradients and a theoretical model were used to estimate the O2 consumption rates of the arteriolar walls. The vascular O2 consumption rates of functional arterioles were >100 times greater than those observed in in vitro experiments. The vascular O2 consumption rate was highest in first-order (1A) arterioles, which are located upstream, and sequentially decreased downstream in 2A and 3A arterioles under normal conditions. During papaverine-induced vasodilation, on the other hand, the O2 consumption rates of the vascular walls decreased to similar levels, suggesting that the high O2 consumption rates of 1A arterioles under normal conditions depend in part on the workload of the vascular smooth muscle. These results strongly support the hypothesis that arteriolar walls consume a significant amount of O2 compared with the surrounding tissue. Furthermore, the reduction of vascular tone of arteriolar walls may facilitate an efficient supply of O2 to the surrounding tissue.

scholarly journals Design and Analysis of a Modified-atmosphere Package for Minimally Processed Romaine Lettuce

1996 ◽  
Vol 121 (4) ◽  
pp. 722-729 ◽  
Author(s):  
Kevin I. Segall ◽  
Martin G. Scanlon
Keyword(s):  
Shelf Life ◽  
Consumption Rate ◽  
Modified Atmosphere Packaging ◽  
Modified Atmosphere ◽  
Packaging Film ◽  
Romaine Lettuce ◽  
Minimally Processed ◽  
Headspace Gas ◽  
Consumption Rates ◽  
Critical Choice

The first goal of this study was to determine the packaging film O2 permeability required to maintain a steady-state O2 concentration of 3% in modified-atmosphere packaging (MAP) of minimally processed romaine lettuce (Lactuca sativa L.). The second goal of the study was to determine the extent to which MAP could preserve lettuce quality and consequently extend product shelf life. Oxygen consumption rates of commercially prepared lettuce samples were determined in a closed system for each of three atmospheres (3% O2 combined with either 6%, 10%, or 14% CO2). Enzymatic, quadratic, and linear mathematical models were compared to determine which best described the respiratory data. The linear model was the most suitable and was used to predict the O2 consumption rate of the minimally processed romaine lettuce under the desired package headspace gas concentrations. The predicted O2 consumption rate was used to calculate the necessary O2 permeability for the packaging film. Packages (21.6 × 25.4 cm) were constructed from a polypropylene-polyethylene-laminate film with the appropriate O2 permeability. Packaged samples were stored under three modified atmospheres (MAs) (3% O2 combined with either 6%, 10%, or 14% CO2) for 20 days, and headspace gas concentrations, lettuce appearance, and color were evaluated every other day. Growth of pectinolytic and lactic acid bacteria was also studied. The O2 consumption rate of the lettuce decreased with increasing CO2 levels. The O2 levels in the MA packages equilibrated at 7% to 11%. Compared to a control atmosphere of air, MAP delayed the development of tissue discoloration. Preliminary results indicated no effect of MAP on microbial growth. Of the three CO2 levels, 10% was slightly more effective than 6% and 14%. Critical choice of packaging permeabilities combined with MAP maintained the quality of minimally processed romaine lettuce and thereby increased shelf life by about 50%.

Performance evaluation of throat type updraft biomass gasifier using different biomass fuels

2021 ◽  
Vol 45 (03) ◽  
pp. 6-12
Author(s):  
D. K. Vyas ◽  
J. Sravankumar ◽  
J. J. Chavda
Keyword(s):  
Power Generation ◽  
Carbon Monoxide ◽  
Chemical Process ◽  
Consumption Rate ◽  
Calorific Value ◽  
Producer Gas ◽  
Saw Dust ◽  
Consumption Rates ◽  
Maize Cobs ◽  
Agro Residues

A biomass gasifier converts solid fuel such as wood waste, saw-dust briquettes and agro-residues into a gaseous fuel through a thermo-chemical process and the resultant gas can be used for thermal and power generation applications. The present research aims to evaluate the updraft biomass gasifier using different biomass for thermal application. The capacity of updraft gasifier was a 5-10 kg.h-1 and three types of biomass: maize cobs, sized wood and saw dust briquettes were used as fuel for producing producer gas by thermal application. The maximum carbon monoxide (CO), hydrogen (H2) and Methane (CH4) found were 14.8, 12.7 and 3.9%, 14.6, 13.7 and 3.9 % and 14.2, 13.5 and 3.9% at 5 kg.h-1 biomass consumption rate, respectively using maize cobs, sized wood and saw dust briquettes as fuel. The maximum and minimum producer gas calorific value was found 1120 and 1034 kcal.m-3; 1139 and 1034 kcal.m-3 and 1123 and 1036 kcal.m-3 at biomass consumption rate of 5 and 10 kg.h-1 using maize cobs, sized wood and saw dust briquettes as fuel respectively. The maximum gasifier efficiency of 77.94, 70.26 and 69.60% was found at the biomass consumption rate of 5 kg.h-1 using maize cobs, sized wood and saw dust briquettes as fuel, respectively. The minimum gasifier efficiency of 72.72, 64.49 and 64.90 % was found at the biomass consumption rate of 10 kg.h-1 using maize cobs, sized wood and saw dust briquettes as fuel in the system, respectively. The maximum overall thermal efficiency of 29.60, 30.65 and 23.69 % were found at the biomass consumption rates of 8, 7 and 7 kg.h-1 using maize cobs, sized wood and saw dust briquettes, respectively.

A comparison of the gill physiology of two euryhaline crab species, Callinectes sapidus and Callinectes similis: energy production, transport-related enzymes and osmoregulation as a function of acclimation salinity

1995 ◽  
Vol 198 (2) ◽  
pp. 349-358 ◽  
Author(s):  
S Piller ◽  
R Henry ◽  
J Doeller ◽  
D Kraus
Keyword(s):  
Oxygen Consumption ◽  
Energy Production ◽  
Consumption Rate ◽  
Callinectes Sapidus ◽  
Crab Species ◽  
Ion Concentrations ◽  
Low Salinity ◽  
Consumption Rates ◽  
Cytochrome Content ◽  
Mitochondrial Cytochromes

Callinectes sapidus and C. similis co-occur in estuarine waters above 15 salinity. Callinectes sapidus also inhabits more dilute waters, but C. similis is rarely found below 15 . Previous work suggests that C. sapidus may be a better hyperosmoregulator than C. similis. In this study, energy metabolism and the levels of transport-related enzymes in excised gills were used as indicators of adaptation to low salinity. Oxygen consumption rates and mitochondrial cytochrome content of excised gills increased in both species as acclimation salinity decreased, but to a significantly greater extent in C. similis gills. In addition, C. similis gills showed the same levels of carbonic anhydrase and Na+/K+-ATPase activities and the same degree of enzyme induction during low-salinity adaptation as has been reported for C. sapidus gills. However, hemolymph osmolality and ion concentrations were consistently lower in C. similis at low salinity than in C. sapidus. Therefore, although gills from low-salinity-acclimated C. similis have a higher oxygen consumption rate and more mitochondrial cytochromes than C. sapidus gills and the same level of transport-related enzymes, C. similis cannot homeostatically regulate their hemolymph to the same extent as C. sapidus.

EAGLE/DTA: A Life Cycle Cost Model for Damage Tolerance Assessment

1983 ◽  
Author(s):  
Edward J. Reed
Keyword(s):  
Life Cycle ◽  
Air Force ◽  
Life Cycle Cost ◽  
Technology Development ◽  
Damage Tolerance ◽  
Low Cycle Fatigue ◽  
Cost Model ◽  
Modeling And Analysis ◽  
Weapon Systems ◽  
Maintenance Requirements

The U.S. Air Force and Pratt & Whitney Aircraft are currently engaged in developing technology to minimize low-cycle fatigue maintenance requirements in future gas turbine engines. The Life Cycle Cost/Damage Tolerance Assessment (LCC/DTA) program is directed toward furthering technology development in two important areas that relate to the overall life cycle cost of advanced Air Force weapon systems: life cycle cost modeling and analysis, and damage tolerance design (DTD). A major goal of the LCC/DTA program is to establish hot-section disk design criteria specifying acceptable levels for life and maintenance actions based on minimum life cycle cost. This paper discusses the methodology developed to evaluate the weapon system LCC impact of designing to damage tolerance criteria.

Do methanotrophs drive phosphorus mineralization in soil ecosystem?

2020 ◽  
Author(s):  
Santosh Ranjan Mohanty ◽  
Adarsh Kumar ◽  
Rakesh Parmar ◽  
Garima Dubey ◽  
Ashok Kumar Patra ◽  
...  
Keyword(s):  
Consumption Rate ◽  
Organic P ◽  
Soil Ecosystem ◽  
Inorganic P ◽  
Sodium Phytate ◽  
Feeding Cycle ◽  
Consumption Rates ◽  
Phosphorus Mineralization ◽  
Absolute Control ◽  
P Sources

Experiments were carried out to elucidate linkage between methane consumption and mineralization of P from different phosphorous sources. The treatments were no CH4 no P amendment absolute control, with CH4 no P amendment control, with CH4 + inorganic P as Ca3(PO4)2 and with CH4 + organic P (sodium phytate). P sources were added at 25 µg P g-1 soil. Soils were incubated to undergo three repeated CH4 feeding cycle referred as feeding cycle I, feeding cycle II, and feeding cycle III. CH4 consumption rate k (µg CH4 consumed g-1 soil d-1) was 0.297 ± 0.028 in no P amendment control, 0.457±0.016 in Ca3(PO4)2, and 0.627 ± 0.013 in sodium phytate. Rate k was stimulated by 2 to 6 times over CH4 feeding cycles and followed the trend of sodium phytate > Ca3(PO4)2 > no P amendment control. CH4 consumption stimulated P solubilization from Ca3(PO4)2 by a factor of 2.86. Acid phosphatase (µg paranitrophenol released g-1 soil h-1) was higher in sodium phytate than no P amendment control. Abundance of 16S rRNA and pmoA genes increased with CH4 consumption rates. The study suggested that CH4 consumption drive mineralization of unavailable inorganic and organic P sources in the soil ecosystem.

Sign in / Sign up

Export Citation Format

Share Document