scholarly journals The effect of absorption process parameters on its efficiency

2018 ◽  
Vol 245 ◽  
pp. 03011
Author(s):  
Valeri Kiss ◽  
Aleksandr Evdokimov ◽  
Tatiana Kaverzneva ◽  
Dmitriy Tarkhov
Keyword(s):  
Aerodynamic Characteristics ◽  
Process Efficiency ◽  
Hydrodynamic Characteristics ◽  
Absorption Process ◽  
Water Vapor Absorption ◽  
Energy Characteristics ◽  
Contact Devices ◽  
Longitudinal Mixing ◽  
Aerodynamic Parameters ◽  
Degree Of Extraction

In this work we are presenting the results of studies of the effect of hydro and aerodynamic parameters of the process of water vapor absorption during intensive bubbling in the dynamic foam mode on the absorption process efficiency. As a result, it was found that the hydrodynamic characteristics (height of the foam layer of the absorbent and its resistance) and aerodynamic characteristics (gas velocity, longitudinal mixing in the gas phase) have the main influence on the efficiency of the absorption process. We also investigated the effect on the efficiency of the process of kinetic characteristics, characterized by the number of transport units and absorption factor. We have proposed to estimate the overall efficiency of the process, taking into account the degree of extraction, as well as the energy characteristics (hydraulic resistance), weight and size characteristics and the drop entrainment volume. For this purpose, for the overall assessment we have proposed to introduce a conditional optimality ratio, allowing to make a comparison of both various contact devices and absorbents.

Effect of Nanoparticles on H2O/LiBr Falling Film Absorption Process

2016 ◽  
Author(s):  
L. Y. Zhang ◽  
Y. Li ◽  
Y. Wang ◽  
L. X. Cao ◽  
X. Z. Meng
Keyword(s):  
Mass Transfer ◽  
Heat And Mass Transfer ◽  
Fe3o4 Nanoparticles ◽  
Falling Film ◽  
Absorption Process ◽  
Nanoparticle Concentration ◽  
Water Vapor Absorption ◽  
Libr Solution ◽  
Falling Film Absorption ◽  
Film Absorption

Absorber is an important component in absorption refrigerating system. Its performance plays a significant role on the overall efficiency of absorption refrigerating system. The nanofluids which can enhance the heat and mass transfer will be utilized to absorber for enhancing the water vapor absorption process and improving the absorber efficiency. The software CFD-FLUENT is used to analyze the falling film absorption process of the nanofluids, which consists of H2O/LiBr solution with Fe3O4 nanoparticles in this paper. The results indicate that the enhancing heat and mass transfer of nanofluids is related to the nanoparticle concentration and size. The stronger the nanoparticle concentration, the greater enhancement of heat and mass transfer of falling film; while the smaller the nanoparticle size, the greater enhancement of heat and mass transfer of falling film. It is also found that the enhancement ratio of heat and mass transfer flux reach 1.48 and 1.37, respectively, as the Fe3O4 nanoparticles mass concentration of 0.01wt% and the size of 50nm.

Numerical study of the aerodynamic and power characteristics of the cycloidal rotor, under incoming flow

2019 ◽  
pp. 25-34
Author(s):  
Александр Анатольевич Дектерев ◽  
Артем Александрович Дектерев ◽  
Юрий Николаевич Горюнов
Keyword(s):  
Flow Velocity ◽  
Numerical Study ◽  
Lift Coefficient ◽  
Simulation Method ◽  
Aerodynamic Characteristics ◽  
Incoming Flow ◽  
Ansys Fluent ◽  
Energy Characteristics ◽  
Power Characteristics ◽  
Calculation Results

Исследование направлено на разработку и апробацию методики численного моделирования аэродинамических и энергетических характеристик циклоидального ротора. За основу взята конфигурация ротора IAT21 L3. Для нее с использованием CFD-пакета ANSYS Fluent построена математическая модель и выполнен расчет. Проанализировано влияние скорости набегающего потока воздуха на движущийся ротор. Математическая модель и полученные результаты исследования могут быть использованы при создании летательных аппаратов с движителями роторного типа. This article addresses the study of the aerodynamic and energy characteristics of a cycloidal rotor subject to the influence of the incoming flow. Cycloidal rotor is one of the perspective devices that provide movement of aircrafts. Despite the fact that the concept of a cycloidal rotor arose in the early twentieth century, the model of a full-scale aircraft has not been yet realized. Foreign scientists have developed models of aircraft ranging in weight from 0.06 to 100 kg. The method of numerical calculation of the cycloidal rotor from the article [1] is considered and realized in this study. The purpose of study was the development and testing of a numerical simulation method for the cycloidal rotor and study aerodynamic and energy characteristics of the rotor in the hovering mode and under the influence of the oncoming flow. The aerodynamic and energy characteristics of the cycloidal rotor, rotating at a speed of 1000 rpm with incoming flow on it with velocities of 20-80 km/h, were calculated. The calculation results showed a directly proportional increase of thrust with an increase of the incoming on the rotor flow velocity, but the power consumed by the rotor was also increased. Increase of the incoming flow velocity leads to the proportional increasing of the lift coefficient and the coefficient of drag. Up to a speed of 80 km/h, an increase in thrust and power is observed; at higher speeds, there is a predominance of nonstationary effects and difficulties in estimating the aerodynamic characteristics of the rotor. In the future, it is planned to consider the 3D formulation of the problem combined with possibility of the flow coming from other sides.

scholarly journals The Effects of Icing on Aircraft Longitudinal Aerodynamic Characteristics

Mathematics ◽  
2020 ◽  
Vol 8 (7) ◽  
pp. 1171
Author(s):  
Yihua Cao ◽  
Wenyuan Tan ◽  
Yuan Su ◽  
Zhongda Xu ◽  
Guo Zhong
Keyword(s):  
Prediction Method ◽  
Flight Test ◽  
Aerodynamic Characteristics ◽  
Identification System ◽  
Narrow Strip ◽  
Aerodynamic Derivatives ◽  
Strip Theory ◽  
Aerodynamic Parameters ◽  
Flight Dynamics Model ◽  
Derivatives Of

To study the effects of ice accretion on the longitudinal aerodynamic characteristics of an aircraft, a two-part method for predicting longitudinal aerodynamic derivatives of iced aircraft is proposed. For the aircraft with a flight test, a parameter identification system based on maximum likelihood criterion and a longitudinal nonlinear flight dynamics model is established. For the aircraft without a flight test, an engineering prediction method of aerodynamic derivatives based on an individual component CFD calculation and narrow strip theory is established. According to the flight test data of DHC-6 Twin Otter aircraft from NASA, the longitudinal aerodynamic parameters of both clean and artificially iced aircraft are obtained. Additionally, the longitudinal aerodynamic derivatives of the iced aircraft are calculated. Then, the correctness of the prediction method is verified by comparing the calculated results with the identification results. The comparison of these results shows that the prediction method is correct and accurate, and it can be used to calculate the effects of icing on the aircraft longitudinal aerodynamic parameters.

scholarly journals Sabot Discard Characteristics under Different Spin Rates of the Rifled Barrel Launching APFSDS

2021 ◽  
Vol 2021 ◽  
pp. 1-18
Author(s):  
Chengqing Zhang ◽  
Huiyuan Wang ◽  
Ting Liu ◽  
Yingxian Duo
Keyword(s):  
Surface Pressure ◽  
Aerodynamic Characteristics ◽  
Intensity Change ◽  
Monitoring Point ◽  
Choked Flow ◽  
Optimal Value ◽  
Perfect Symmetry ◽  
Computational Fluid Dynamics Cfd ◽  
Aerodynamic Parameters ◽  
Quantization Parameters

The sabot discard asymmetry caused by spinning affects the exterior ballistic characteristics and shooting accuracy of a gun with the rifled barrel. To gain a deeper understanding of the complex sabot discard performance for the armor-piercing, fin-stabilized discarding sabot (APFSDS), a numerical investigation is performed to assess the effects of the spin rate on the sabot discard characteristics. We obtain the calculation boundary by the interior ballistics and the firing conditions and carry out a numerical simulation under different spin rates using computational fluid dynamics (CFD) and a dynamic mesh technique. We analyze four aspects of sabot discard characteristics, namely, sabot separation, rod surface pressure, rod aerodynamic parameters, and discarding quantization parameters. Computational results show that the sabot separation nearly presents perfect symmetry at 0 rad/s, and when the initial rate of the sabot increases, there is more obvious separation asymmetry, and it contributes to the relative position variation among the sabots and the rod. The distinction of rod surface pressure indicates that the choked flow is the strongest flow source, and the spin rate has almost no effect on the pressure of the rod front part. When the monitoring point moves towards the fins, the pressure distribution and intensity change more dramatically. The initial spin rate and separation asymmetry produce a variation in the surface pressure, which further influences the rod aerodynamic characteristics. The discarding quantization parameters exhibit a certain variation rule with its spin rate. 2,000 rad/s has a significant influence on the rod aerodynamic coefficients during the weak coupling phase. When the spin rate is in the range of 0–900 rad/s, the discarding characteristics remain the same. However, when the spin rate exceeds 900 rad/s, the separation time and aerodynamic impulse have a quadratic polynomial relationship with the rate. Additionally, a spin rate of 1,000 rad/s is the optimal value for a rifled barrel gun.

Experimental Investigation on Aerodynamic Characteristics of a Variable Area Nozzleless Volute

1985 ◽  
Author(s):  
Feng Zhenping ◽  
Shen Zuda ◽  
Xiang Yimin
Keyword(s):  
Experimental Investigation ◽  
Aerodynamic Characteristics ◽  
Sectional Area ◽  
Cross Sectional ◽  
Flow Angle ◽  
Rate Range ◽  
Flow Parameters ◽  
Outlet Flow ◽  
Flow Rate Range ◽  
Aerodynamic Parameters

The aerodynamic characteristics of a variable area nozzleless volute (VAV) for small radial inflow turbines are studied with the aid of cold air tests in which flow parameters inside the volute channel and at the outlet of the nozzleless ring are measured for cases of various cross-sectional areas. The experimental investigation shows that the desired aerodynamic parameters, especially the outlet flow angle α1 as well as the mass flow rate range can be obtained by varying the croes-sectional area of the VAV. A reasonable approximate method for calculating the average outlet flow angle α1 is presented in which the variation of the circulation in the flow is taken into account.

scholarly journals New Flotation Reagents on the Base of Tetrahydropyran for the Processing of High-Ash Coals

2019 ◽  
Vol 21 (3) ◽  
pp. 277
Author(s):  
T. Ketegenov ◽  
S. Kalugin ◽  
Zh. Asylkhanov ◽  
K. Kamunur ◽  
A. Karagulanova
Keyword(s):  
Heterocyclic Compound ◽  
Picric Acid ◽  
Process Efficiency ◽  
Resonance Spectroscopy ◽  
Flotation Reagents ◽  
Synthesis Time ◽  
Coal Flotation ◽  
Study Results ◽  
High Ash Coal ◽  
Degree Of Extraction

The given paper presents the study results of flotation benefication of high-ash coals with new flotation reagent on the base of acetate of 3-amyltetrahydro-pyran- 4-ol which incorporates apolar and heteropolar groups. The use of a picric acid as a catalyst of hydroxymethylation reaction instead of sulfuric acid made it possible to halve the synthesis time and increase the yield of the target product. The structure of the obtained heterocyclic compound was identified by elemental analysis, infrared spectroscopy (IR) and nuclear magnetic resonance spectroscopy (NMR). Waste of high-ash coal production from the Saryadyr deposit (Kazakhstan) was selected as an object of flotation. It is found that the benefication process efficiency depends on the fineness of the coal material and increases with the transition from -0.8 + 0.4 mm to -0.2 + 0.08 mm. Comparison of the efficiency of coal flotation using pine oil as a traditional collector and 3-amyltetrahydropyran-4-ol acetate showed an increase in the degree of extraction of coal mass into a concentrate and a simultaneous decrease in its ash content when using a synthesized heterocyclic compound. It is concluded that 3-amyltetrahydropyran-4-ol acetate shows both a modifying effect and a foaming ability.

The Effects of Different Support Forms on the Aerodynamic Characteristics of the High-Speed Train Model

2012 ◽  
Vol 246-247 ◽  
pp. 461-465
Author(s):  
Bao Yu Li ◽  
Xi Zhuang Shan ◽  
Zhi Gang Yang
Keyword(s):  
Flow Field ◽  
High Speed ◽  
Aerodynamic Characteristics ◽  
Operating Conditions ◽  
High Speed Train ◽  
Reference Velocity ◽  
Computational Fluid Dynamics Cfd ◽  
Aerodynamic Parameters ◽  
Support Interference ◽  
Good Support

By the method of computational fluid dynamics (CFD), this paper calculates the aerodynamic parameters of one complex high-speed train model which adopts different support forms when the reference velocity is 70m/s under different operating conditions. It also analyses the support interference mechanism from the point of flow field structure. The results show that the distributed cylinder support form causes least interference on the model, while the single big cylinder support forms change the flow field structures much which leads to much change of the aerodynamic parameters of the model. The distributed cylinder support form can be applied as a good support form for the high-speed train wind tunnel tests.

scholarly journals Aerodynamic characteristics in upper airways among orthodontic patients and its association with adenoid nasopharyngeal ratios in lateral cephalograms

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Xin Feng ◽  
Yicheng Chen ◽  
Weihua Cai ◽  
Stein Atle Lie ◽  
Kristina Hellén-Halme ◽  
...  
Keyword(s):  
Cfd Simulation ◽  
Aerodynamic Characteristics ◽  
Upper Airways ◽  
Lateral Cephalogram ◽  
Lateral Cephalograms ◽  
Significant Difference ◽  
Orthodontic Patients ◽  
Aerodynamic Parameters ◽  
Group 2 ◽  
Group 1

Abstract Background Adenoid hypertrophy among orthodontic patients may be detected in lateral cephalograms. The study investigates the aerodynamic characteristics within the upper airway (UA) by means of computational fluid dynamics (CFD) simulation. Furthermore, airflow features are compared between subgroups according to the adenoidal nasopharyngeal (AN) ratios. Methods This retrospective study included thirty-five patients aged 9–15 years having both lateral cephalogram and cone beam computed tomography (CBCT) imaging that covered the UA region. The cases were divided into two subgroups according to the AN ratios measured on the lateral cephalograms: Group 1 with an AN ratio < 0.6 and Group 2 with an AN ratio ≥ 0.6. Based on the CBCT images, segmented UA models were created and the aerodynamic characteristics at inspiration and expiration were simulated by the CFD method for the two groups. The studied aerodynamic parameters were pressure drop (ΔP), maximum midsagittal velocity (Vms), maximum wall shear stress (Pws), and minimum wall static pressure (Pw). Results The maximum Vms exhibits nearly 30% increases in Group 2 at both inspiration (p = 0.013) and expiration (p = 0.045) compared to Group 1. For the other aerodynamic parameters such as ΔP, the maximum Pws, and minimum Pw, no significant difference is found between the two groups. Conclusions The maximum Vms seems to be the most sensitive aerodynamic parameter for the groups of cases. An AN ratio of more than 0.6 measured on a lateral cephalogram may associate with a noticeably increased maximum Vms, which could assist clinicians in estimating the airflow features in the UA.

scholarly journals Adaptive Wing Morphing Strategy and Flight Control Method of a Morphing Aircraft Based on Reinforcement Learning

2019 ◽  
Vol 37 (4) ◽  
pp. 656-663
Author(s):  
Binbin Yan ◽  
Yong Li ◽  
Pei Dai ◽  
Muzeng Xing
Keyword(s):  
Reinforcement Learning ◽  
Flight Control ◽  
Control Method ◽  
Sliding Mode ◽  
Normal Load ◽  
Aerodynamic Characteristics ◽  
Morphing Aircraft ◽  
Adaptive Wing ◽  
Aerodynamic Parameters ◽  
Wing Morphing

The morphing aircraft can change different wing shapes or geometries to achieve the optimal flight performance according to various mission scenarios. In this paper, DATCOM is used to calculate aerodynamic parameters based on Firebee UAV morphing aircraft with different wing configurations and analyze aerodynamic characteristics. A novel adaptive wing morphing strategy for morphing aircraft based on reinforcement learning method is proposed. This method can highly meet the demand of keeping optimal performance in multiple flight conditions, and the adaptive wing morphing strategy, three-loop normal load altitude controller and sliding mode velocity controller can together make sure stability of morphing aircraft during morphing process with good tracking performance.

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