Low temperature characteristic analysis and enhancement of hydraulic system on high-altitude and long-endurance unmanned vehicle

2016 ◽  
Author(s):  
Longxian Xue ◽  
Dongli Ma ◽  
Xuhui Wang
Keyword(s):  
Low Temperature ◽  
High Altitude ◽  
Hydraulic System ◽  
Temperature Characteristic ◽  
Characteristic Analysis ◽  
Unmanned Vehicle ◽  
Long Endurance

Dynamic Analysis of the Joined-Wing Configuration in High-Altitude Long-Endurance Aircraft Using Fluid-Structure Interaction Model

2007 ◽  
Author(s):  
Prabu Ganesh Ravindren ◽  
Kirti Ghia ◽  
Urmila Ghia
Keyword(s):  
Finite Element ◽  
High Altitude ◽  
Fluid Structure Interaction ◽  
Structural Deformation ◽  
Time Step ◽  
Fluid Structure ◽  
Structure Interaction ◽  
Finite Element Software ◽  
Joined Wing ◽  
Long Endurance

Recent studies of the joined-wing configuration of the High Altitude Long Endurance (HALE) aircraft have been performed by analyzing the aerodynamic and structural behaviors separately. In the present work, a fluid-structure interaction (FSI) analysis is performed, where the fluid pressure on the wing, and the corresponding non-linear structural deformation, are analyzed simultaneously using a finite-element matrix which couples both fluid and structural solution vectors. An unsteady, viscous flow past the high-aspect ratio wing causes it to undergo large deflections, thus changing the domain shape at each time step. The finite element software ANSYS 11.0 is used for the structural analysis and CFX 11.0 is used for the fluid analysis. The structural mesh of the semi-monocoque joined-wing consists of finite elements to model the skin panel, ribs and spars. Appropriate mass and stress distributions are applied across the joined-wing structure [Kaloyanova et al. (2005)], which has been optimized in order to reduce global and local buckling. The fluid region is meshed with very high mesh density at the fluid-structure interface and where flow separation is predicted across the joint of the wing. The FSI module uses a sequentially-coupled finite element equation, where the main coupling matrix utilizes the direction of the normal vector defined for each pair of coincident fluid and structural element faces at the interface [ANSYS 11.0 Documentation]. The k-omega turbulence model captures the fine-scale turbulence effects in the flow. An angle of attack of 12°, at a Mach number of 0.6 [Rangarajan et al. (2003)], is used in the simulation. A 1-way FSI analysis has been performed to verify the proper transfer of loads across the fluid-structure interface. The CFX pressure results on the wing were transferred across the comparatively coarser mesh on the structural surface. A maximum deflection of 16 ft is found at the wing tip with a calculated lift coefficient of 1.35. The results have been compared with the previous study and have proven to be highly accurate. This will be taken as the first step for the 2-way simulation. The effect of a coupled 2-way FSI analysis on the HALE aircraft joined wing configuration will be shown. The structural deformation history will be presented, showing the displacement of the joined-wing, along the wing span over a period of aerodynamic loading. The fluid-structure interface meshing and the convergence at each time step, based on the quantities transferred across the interface will also be discussed.

scholarly journals Study on the Geological Condition Analysis and Grade Division of High Altitude and Cold Stope Slope

2021 ◽  
Vol 13 (22) ◽  
pp. 12464
Author(s):  
Ruichong Zhang ◽  
Shiwei Wu ◽  
Chenyu Xie ◽  
Qingfa Chen
Keyword(s):  
Low Temperature ◽  
High Altitude ◽  
Stable State ◽  
Geological Condition ◽  
Rock Layer ◽  
Eastern Slope ◽  
Geological Conditions ◽  
Grade Ii ◽  
Grade Division ◽  
Grade Iii

Analysis of the geological conditions of high-altitude and low-temperature stope slopes and the study of grade division are the basis for the evaluation of slope stability. Based on the engineering background of the eastern slope of the Preparatory iron mine in Hejing County, Xinjiang, we comprehensively analyse and summarize the factors that affect the geological conditions of high-altitude and cold slopes and finally determine nine geological conditions that affect the index parameters. Based on a back-propagation (BP) neural network algorithm, we establish an applicable network model to analyse the geological conditions of slopes in cold areas. The model is applied to the eastern slope to analyse and classify the geological conditions of the high-altitude and low-temperature slopes. The research results show that the skarn rock layer in the eastern slope is in a stable state and not prone to landslides, and its corresponding geological condition is Grade I; meanwhile, the monzonite porphyry rock layer is in a relatively stable state, with a potential for landslides and a corresponding geological condition Grade II. The marble rock layer is in a generally stable state, there is the possibility of landslide accidents, and the corresponding geological condition level is Grade III. The limestone rock layer is in an unstable state and prone to landslide accidents, it has a corresponding geology condition Grade IV. Therefore, the eastern slope can be divided into different geological condition regions: Zone I, Zone II, Zone III, and Zone IV, and the corresponding geological condition levels for these are Grade I, Grade II, Grade III, and Grade IV. These results may provide a basis for the stability evaluation of high altitudes and cold slopes.

scholarly journals Diversity and Distribution of Bracket Fungi in Mt. Kilakiron, Bukidnon, Philippines

2021 ◽  
Vol 13 (1) ◽  
pp. 41-50
Author(s):  
Mc Arthur Lequin Cababan ◽  
Aprille Kake Ora Jaranilla ◽  
Mariane Catayas Bastatas ◽  
Chazzel Feel Comonong Salvane ◽  
Uzziel Campuso Toldo
Keyword(s):  
Low Temperature ◽  
Nutrient Cycling ◽  
High Altitude ◽  
Environmental Factor ◽  
Trametes Versicolor ◽  
Diversity Index ◽  
Large Contribution ◽  
Floristic Survey ◽  
Symbiotic Relationships ◽  
Total Species

Fungi have a lot of important function in the bionetwork resembling to decomposition and even nutrient cycling with respect to its symbiotic relationships with trees and other plants. This study aimed to assess the diversity and distribution of bracket fungi in Mt. Kilakiron, Portulin, Pangantucan, Bukidnon. Thus, floristic survey was conducted in one of the mountain of Mindanao to provide information as to what and how many species of bracket fungi are present in Mt. Kilakioron, Bukidnon, Philippines.  40 total species belonging to 17 genera and 5 family was collected and assessed. 12 individuals of Trametes versicolor were observe which favors dwellings with low temperature and high altitude are. Additionally, study revealed that most types of bracket fungi initiate in the site are decomposers and saprophytic in nature which contributes a lot in the process of putrefaction. The species of bracket fungi in Mt. Kilakiron clearly shows abundant and provides a large contribution to the ecosystem having high Shannon diversity index. The significance of each environmental factor is discussed in relationship to the ecology of the species. Bracket fungi are reliant on the climatic and conservational settings which makes them as excellent natural pointers of ecosystem in the forests of Mindanao Island, Philippines.

Unimpeded migration of ions in carbon electrodes with bimodal pores at an ultralow temperature of −100 °C

2019 ◽  
Vol 7 (27) ◽  
pp. 16339-16346 ◽  
Author(s):  
Xi Wang ◽  
Jiang Xu ◽  
Joselito M. Razal ◽  
Ningyi Yuan ◽  
Xiaoshuang Zhou ◽  
...  
Keyword(s):  
Energy Storage ◽  
Low Temperature ◽  
High Altitude ◽  
Space Missions ◽  
Carbon Electrodes ◽  
Discharge Energy ◽  
Energy Storage Devices ◽  
Storage Devices ◽  
Ultralow Temperature ◽  
Temperature Applications

The ability to rapidly charge (and discharge) energy storage devices at extremely low temperature (down to −100 °C) is critical for low-temperature applications such as high altitude exploration and space missions.

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