scholarly journals Experimental Study on the Influence of Water and Cavitation on Propeller Load during Ice-Propeller Milling

2021 ◽  
Vol 11 (24) ◽  
pp. 11578
Author(s):  
Pei Xu ◽  
Chao Wang ◽  
Liyu Ye
Keyword(s):  
Tangential Force ◽  
Milling Process ◽  
Water Ice ◽  
Test Platform ◽  
Influence Of Water ◽  
Bearing Force ◽  
Combined Action ◽  
Ice Water ◽  
Thrust And Torque ◽  
Propeller Thrust

When the ice-class propeller sails in an icy sea, it is affected by external factors such as water, ice, and cavitation, and the process of mutual interference is extremely complicated. In order to study the influence of water and cavitation on propeller load during the ice-propeller milling process, a test platform for ice–water propeller milling action was constructed. The load and cavitation of the propeller and single blade were measured during ice-propeller milling in air and water (atmospheric pressure and decompression conditions). Simultaneously, the changes in the load and bearing force of the propeller and blade were studied at different working conditions. The results show that, in the process of ice–water propeller milling, the direction of the propeller thrust generated by the water is opposite to that of the axial force generated by ice; the combined action of the two causes propeller thrust loss, whereas the combined action of water and ice increases propeller torque. The presence of water increases the thrust, torque, and bearing force of the fluctuating amplitude of the blade. The occurrence of cavitation reduces the thrust and torque of the propeller and blade and increases thrust fluctuating amplitudes while decreasing the tangential force fluctuating amplitude of the blade.

scholarly journals Influence of water ice clouds on Martian tropical atmospheric temperatures

2008 ◽  
Vol 35 (7) ◽  
pp. n/a-n/a ◽  
Author(s):  
R. John Wilson ◽  
Stephen R. Lewis ◽  
Luca Montabone ◽  
Michael D. Smith
Keyword(s):  
Ice Clouds ◽  
Water Ice ◽  
Influence Of Water

Towards a nudging of stratospheric overshoots in the 3D mesoscale BRAMS model

2021 ◽  
Author(s):  
Justine Pichon ◽  
Emmanuel Riviere ◽  
Abhinna Behera ◽  
Jeremie Burgalat
Keyword(s):  
Mesoscale Model ◽  
Water Concentration ◽  
Global Scale ◽  
Satellite Measurement ◽  
Model Categories ◽  
Tropical Regions ◽  
Water Ice ◽  
Convective Clouds ◽  
Starting Point ◽  
Ice Water

<p>Water repartition in the stratosphere is a key compound in the atmospheric chemical and<br>radiative equilibrium. Since the 80’s, an increase of the water concentration in the<br>stratosphere has been observed.This presence in the stratosphere can be explained by the<br>slow ascent of air mass above convective clouds in tropical regions. The amount of water<br>vapor entering in the stratosphere depends on the coldest temperature and countered<br>during this slow ascent because it can lead to ice cristal formation that sediment and<br>dehydrate the air masses. But some other processes may contribute to the stratospheric<br>water budget, especially to explain the increase of water vapor. Stratospheric overshoots<br>phenomenon can take part in the stratospheric hydratation, by injecting directly water ice in<br>the stratosphere. Injected ice water, by sublimation, will hydrate stratosphere locally. The<br>local role of overshoots is better known but their contributions at the global scale steal need<br>to be quantified. In order to estimate this contribution, previous studies have used the 3D<br>simulation mesoscale model BRAMS to show overshoot impact in the upper Tropical<br>Tropopause Layer (TTL). These studies are the starting point of our study.</p><p>The aim of this paper is to present the new development inside BRAMS to nudge<br>stratospheric ice injection by overshoots. It uses an overshoot occurrence climatology from<br>MHS (Microwave Humidity Sounder) satellite measurement. Ice injection in the model is<br>made according to ice model categories previously shown to be present in the overshoot<br>plumes with ratios already diagnosed in previous studies. Ice injection is made between two<br>layers of TTL’s stratospheric part: between 380 and 385K and between 385 et 400K. Nudging<br>is triggered only if, in the grid mesh (20 x 20 km) where MHS has detected an overshoot,<br>BRAMS computes a cumulonimbus with a top above 13.5km. For the layer above 385 K<br>isentrope, a subgrid box of 2 km x 2 km is considered for the computation of ice injection.<br>Sensibility test of this nudging scheme will be presented in this presentation. </p>

Optimization Based Geometric Modeling of Nano/Micro Scale Ion Milling of Organic Materials

2009 ◽  
Author(s):  
Jing Fu ◽  
Sanjay B. Joshi
Keyword(s):  
Geometric Modeling ◽  
Focused Ion Beam ◽  
Organic Materials ◽  
Ion Beam ◽  
Target Material ◽  
Milling Process ◽  
Ion Milling ◽  
Flexible Tool ◽  
Water Ice ◽  
Micro Scale

Recently, Focused Ion Beam (FIB) instruments have begun be applied to organic materials such as polymers and biological systems. This provides a novel tool for sectioning biological samples for analysis, or microfabrication with environment friendly materials. The modeling of nano/micro scale geometry accurately sculptured by FIB milling is crucial for generating the milling plan and process control, and for computer simulation for prediction and visualization of the milled geometry. However, modeling of the ion milling process on compound materials, especially for high aspect ratio feature, is still difficult due to the complexity of target material, as well as multiple physical and chemical interactions involved. In this study, a comprehensive model of ion milling with organic targets is presented to address the challenges using a simulation based approach. This platform has also been validated by milling different features on water ice in a cryogenic environment, and the simulation and experiment results show great consistency. With the proliferation of nanotechnology to biomedical and biomaterial domains, the proposed approach is expected to be a flexible tool for various applications involving novel and heterogeneous milling targets.

Influence Analysis of Blade Fracture on Hydrodynamic Performance of Ducted Propellers Based on CFD

2013 ◽  
Vol 300-301 ◽  
pp. 1071-1076 ◽  
Author(s):  
Li Jian Ou ◽  
De Yu Li ◽  
Wei Zhang
Keyword(s):  
Numerical Model ◽  
Periodic Variation ◽  
Hydrodynamic Performance ◽  
Normal Variation ◽  
Current Field ◽  
Force Coefficient ◽  
Ducted Propeller ◽  
Bearing Force ◽  
Thrust And Torque ◽  
Ducted Propellers

The numerical model of the unsteady flow field of ducted propellers is based on CFD (computational fluid dynamics). By applying the numerical model, the unsteady hydrodynamic performance of the ducted propeller with the fracture at different positions of a certain blade is numerically analyzed under three different wake current fields. Based on regress analysis ,the relationships between the mean KQ、mean KT and the quantity of the blade fracture of ducted propellers are obtained; and the relationships between hydrodynamic coefficients Kp, KQ, KFy (Bearing force coefficient of the propeller) and wake current fields , the quantity of the blade fracture are respectively further analyzed. The results show that: (1) with the increase of the quantity of the blade fracture, the amplitude of bearing force periodic variation of propellers increases, while the thrust and torque reduce; (2) the bearing force of propellers is similarly sine-varying, and the frequency of its variation is unrelated to the normal variation frequency of the wake current field. The more non-uniform the wake current field is, the more the amplitude of its periodic variation is; (3) the thrust and torque of propeller are similarly sine-varying, and the frequencies of their variation are related to the normal variation frequency of the wake current field. And the frequencies equal the shaft frequency multiplied the normal variation frequency of the wake current field. The more non-uniform the wake current field is, the more the amplitude of their periodic variation is.

Unsteady Hydrodynamic Performance Prediction of Ducted Propeller Based on CFD

2013 ◽  
Vol 437 ◽  
pp. 32-35
Author(s):  
Li Jian Ou ◽  
Nan Huo Wu ◽  
De Yu Li
Keyword(s):  
Performance Prediction ◽  
Open Water ◽  
Hydrodynamic Performance ◽  
Moving Mesh Method ◽  
Ducted Propeller ◽  
Mesh Method ◽  
Bearing Force ◽  
Thrust And Torque ◽  
Wake Fields ◽  
Calculated Model

Firstly, the calculated model was created in UG and GAMBIT, and then the Moving Mesh method was adopted to simulate thrust and torque of ducted propeller using FLUENT in the open water. The thrust, torque and bearing force of ducted propeller in three different wake fields were calculated. And the influence on the performance of ducted propeller by the wake fields was analyzed.

scholarly journals Impact flash evolution of CO 2 ice, water ice, and frozen Martian and lunar regolith simulant targets

2020 ◽  
Vol 55 (10) ◽  
pp. 2301-2319
Author(s):  
Jon D. Tandy ◽  
Mark C. Price ◽  
Penny J. Wozniakiewicz ◽  
Mike J. Cole ◽  
Luke S. Alesbrook ◽  
...  
Keyword(s):  
Lunar Regolith ◽  
Water Ice ◽  
Lunar Regolith Simulant ◽  
Ice Water ◽  
Impact Flash

A Propeller Thrust and Torque Dynamometer for Wind Tunnel Models

Strain ◽  
2002 ◽  
Vol 38 (1) ◽  
pp. 3-10 ◽  
Author(s):  
A. F. Molland ◽  
S. R. Turnock
Keyword(s):  
Wind Tunnel ◽  
Thrust And Torque ◽  
Propeller Thrust

scholarly journals Geochemical barriers as a form of self-organization of geochemical systems (case of study Kerch Peninsula, Russia)

2019 ◽  
Vol 98 ◽  
pp. 01027 ◽  
Author(s):  
Aleksandr Khaustov ◽  
Margarita Redina ◽  
Eugeniya Yakovleva
Keyword(s):  
Heterogeneous Media ◽  
Sharp Change ◽  
Water Ice ◽  
Geochemical Barriers ◽  
Kerch Peninsula ◽  
Geochemical Study ◽  
Polycyclic Aromatic ◽  
Living Organisms ◽  
Water Plants ◽  
Ice Water

According to the author's concept, discharge of groundwater to the surface is considered as a sharp change of geochemical conditions, leading to the formation of geochemical barriers (GCB). In the article presented results of geochemical study of groundwater-soil-organic matter-gas interaction as example of Kerch Peninsula self-organizing system The geochemical barriers give rise to the formation of a kind of non-equilibrium geoecosystems with an individual structure of direct and inverse connections between the components, size and borders of geochemical systems (GCS) are determined by many factors: frequency and scale of discharge, chemical composition, temperature of the source and of the environment, phase transitions within the system with interacting heterogeneous media: "water – rocks", "water – atmosphere", "water – ice", "water – soil", "water – plants (including algae and other living organisms)", and etc. Polycyclic aromatic hydrocarbons (PAHs) are used as tracers of this interaction.

High-Speed Milling Characteristics and the Residual Stresses Control Methods Analysis of Thin-Walled Parts

2011 ◽  
Vol 223 ◽  
pp. 456-463 ◽  
Author(s):  
Bei Zhi Li ◽  
Xiao Hui Jiang ◽  
Huai Jing Jing ◽  
Xiao Yan Zuo
Keyword(s):  
Residual Stress ◽  
Tensile Stress ◽  
Cutting Force ◽  
High Speed ◽  
Tangential Force ◽  
Cutting Temperature ◽  
Milling Process ◽  
Residual Tensile Stress ◽  
High Speed Milling ◽  
Thin Walled

With FEM software of AdvantEdge, a model was created to analyze cutting force and thermal in the high-speed milling process, this model included a complete milling process of cutter radius. Combined with experiments validation, in high-speed milling, the normal force is greater than the tangential force and result in greater residual stress of that direction, which indicates that mechanical force play an essential part on the formation of residual stress. When the speed is over certain scope, the cutting force decreases, but the cutting temperature has been rising. In Roughing, by limiting the range of high-speed the residual tensile stress impact can be reduced. While in finishing, as the feed rate reducing the residual tensile stress will decrease greatly, improving the surface quality of thin-walled parts.

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