Numerical Simulation of the Fan Noise Radiated Through a Semi-Buried Air Inlet

2009 ◽  
Author(s):  
Eric Manoha ◽  
Daniel-Ciprian Mincu
Keyword(s):  
Numerical Simulation ◽  
Fan Noise ◽  
Air Inlet

Numerical Simulation Study of a New Type Solar Collector Wall System

2013 ◽  
Vol 860-863 ◽  
pp. 98-102
Author(s):  
Shu Hui Xu ◽  
Feng Jiao Zhang ◽  
Jian Kai Wang ◽  
Chang Liu
Keyword(s):  
Numerical Simulation ◽  
Velocity Field ◽  
Simulation Study ◽  
Solar Collector ◽  
Collection Efficiency ◽  
Inlet Velocity ◽  
Air Inlet ◽  
New Type ◽  
Collecting Efficiency ◽  
Wall System

In this paper, a new kind of solar collector wall system was designed. Numerical simulation for the orifice plate solar collector wall was carried out to analyze the change of the distributions of the temperature and velocity and the heat collecting efficiency under the conditions of different air inlet velocity. The results shows that the temperature stratification decreases with the increase of the inlet velocity, and the velocity field stratification enhances with the increase of the inlet velocity, and the collection efficiency first increases then decreases with the constantly increasing inlet velocity, and the collection efficiency is the highest when the inlet velocity is 2.5 m/s, up to 81.34%.

Numerical Simulation of 3-D Chemical Non-Equilibrium Flow in the Afterburning Chamber of Solid Ducked Rocket

2011 ◽  
Vol 130-134 ◽  
pp. 3151-3154
Author(s):  
Li Kun Cui ◽  
Yong Zhi Zhang ◽  
Zhuo Li
Keyword(s):  
Numerical Simulation ◽  
Radical Reaction ◽  
Combustion Efficiency ◽  
Equilibrium Flow ◽  
Air Inlet ◽  
Afterburning Chamber ◽  
Inlet Angle ◽  
Fundamental Equations ◽  
Combustion Processes ◽  
Non Equilibrium

In order to reveal the complex turbulent combustion processes in the afterburning chamber of Solid Ducked Rocket (SDR), Based on the fundamental equations of hydrokinetics and elementary principles of radical reaction kinetics, using multi-component chemical reaction equation of containing Mg and Al components, the numerical simulation of chemical non-equilibrium flow in the afterburning chamber of SDR is processed and effects of the air inlet angle on the afterburning chamber is studied by using Fluent software. The results show that pressure distribution is more balanced, temperature distribution is very uneven and flow is extremely complicated in the afterburning chamber. Combustion efficiency can be increased by improving the air inlet angle.

High-speed impact assessment for composite air inlet

2019 ◽  
Vol 11 (5) ◽  
pp. 723-736
Author(s):  
Radek Doubrava ◽  
Martin Oberthor ◽  
Petr Bělský ◽  
Jan Raška
Keyword(s):  
Numerical Simulation ◽  
Composite Structure ◽  
High Speed ◽  
Numerical Models ◽  
Impact Resistance ◽  
High Speed Camera ◽  
Content Type ◽  
High Speed Impact ◽  
Air Inlet ◽  
Final Design

Purpose The purpose of this paper is to describe the approach for the design of a jet engine composite air inlet for a new generation of jet trainer aircraft from the perspective of airworthiness requirements regarding high-speed impact resistance. Design/methodology/approach Validated numerical simulation was applied to flat test panels. The final design was optimised and verified by validated numerical simulation and verified by testing on a full-scale demonstrator. High-speed camera measurement and non-destructive testing (NDT) results were used for the verification of the numerical models. Findings The test results of flat test panels confirmed the high durability of the composite structure during inclined high-speed impact with a near-real jet inlet load boundary condition. Research limitations/implications Owing to the sensitivity of the composite material on technology production, the results are limited by the material used and the production technology. Practical implications The application of flat test panels for the verification and tuning of numerical models allows optimised final design of the air inlet and reduces the risk of structural non-compliance during verification tests. Originality/value Numerical models were verified for simulation of the real composite structure based on high-speed camera results and NDT inspection after impact. The proposed numerical model was simplified for application in a real complex design and reduced calculation time.

scholarly journals Investigation of Throttling Characteristics in Supersonic Polyclinic Inlet

2019 ◽  
pp. 21-33
Author(s):  
D.A. Vnuchkov ◽  
V.I. Zvegintsev ◽  
D.G. Nalivaychenko
Keyword(s):  
Numerical Simulation ◽  
Experimental Investigation ◽  
Wind Tunnel ◽  
Flow Field ◽  
Air Flow ◽  
Flow Restriction ◽  
Air Inlet ◽  
Additional Heating ◽  
Flat Flow ◽  
Good Agreement

This paper presents an experimental investigation of throttling characteristics of a multi-wedge air inlet of a wind tunnel built for flat flow field at M = 2.5. The experiments were performed in a wind tunnel at M numbers of 2.55, 3.05 and 4.05. Results of numerical simulation of the flow in the air inlet, where air flow restriction was implemented by additional heating of the flow in the channel past the air inlet, are given for comparison. Experimental throttling characteristics are in good agreement with the values obtained from computations

scholarly journals An Image Based Mathematical Model for the Propagation of Fan Noise in a Plenum with Large Side Openings

2015 ◽  
Vol 2015 ◽  
pp. 1-8
Author(s):  
Michael J. Panza
Keyword(s):  
Mathematical Model ◽  
Side Wall ◽  
Group Model ◽  
Image Model ◽  
Zero Sound ◽  
Noise Sources ◽  
Fan Noise ◽  
Air Inlet ◽  
Source Orientation ◽  
Reflecting Surfaces

This paper presents another application of an images group model for a special enclosure geometry and source orientation. A previous work outlined the concept via application to a special tight-fitting enclosure. Application of the concept to a fan plenum requires different mathematical descriptions for the image groups. This paper describes the sound reverberation inside a sound enclosure with mostly open sides where the primary noise sources are the air inlets and exhausts of axial type fans located at the top of the enclosure, the sound transmission through the air inlet openings, and the radiation to wayside positions. The main reverberation between the floor and ceiling is determined with an image based mathematical model. The model considers how the main reverberant part image group is amplified by its images from two parallel bulkheads and any side wall frame members. The method of images approach allows the hard surfaces of an untreated plenum to be represented by perfectly reflecting surfaces with zero sound absorption coefficients, thus not requiring any estimate or measurement for these surfaces. Numerical results show excellent comparison to experimental results for an actual plenum. The image model is also shown to be significantly more accurate than the standard large room diffuse field reverberant model.

scholarly journals Numerical Investigation of Water Film Evaporation with the Countercurrent Air in the Asymmetric Heating Rectangular Channel for Passive Containment Cooling System

2020 ◽  
Vol 2020 ◽  
pp. 1-17
Author(s):  
Kashuai Du ◽  
Po Hu ◽  
Zhen Hu
Keyword(s):  
Heat Transfer ◽  
Numerical Simulation ◽  
Cooling System ◽  
Rectangular Channel ◽  
Water Film ◽  
Annular Channel ◽  
Countercurrent Flow ◽  
Film Evaporation ◽  
Air Inlet ◽  
Asymmetric Heating

Passive containment cooling system (PCCS) is an important passive safety facility in the large advanced pressurized water reactor. Using the physical laws, such as gravity and buoyancy, the water film/air countercurrent flow is formed in the external annular channel to keep inside temperature and pressure below the maximum design values. Due to the large curvature radius of the annular channel, one of the short arc segments is taken out, as a rectangular channel, to analyze the main water film evaporation heat transfer characteristics. Two numerical methods are used to predict the water film evaporative mass flow rate during the heat transfer process in the large-scale rectangular channel with asymmetric heating when the water film temperature is not saturated. At the same time, these numerical simulation results are validated by the experiment which is set up to study water film/air countercurrent flow heat transfer on a vertical back heating plate with 5 m in length and 1.2 m in width. It is shown that the maximum deviation between numerical simulation and experiment is 30%. In addition, the influences on these parameters, such as heat flux, evaporative mass flow rate, and water film thickness, are evaluated under the different tilted angles of the rectangular channel and horizontal plane, water/air inlet flow rates, water/air inlet temperatures, heating surface temperatures, and air inlet relative humidities. All these results can provide a good guidance for the design of PCCS in the future.

Analysis of tilted neutral planes for tall space fires with unsymmetrical openings using numerical simulation and Schlieren photography technique

2019 ◽  
Vol 29 (11) ◽  
pp. 4213-4236
Author(s):  
ChungHwei Su ◽  
ShiuanCheng Wang
Keyword(s):  
Numerical Simulation ◽  
Simulation Method ◽  
Neutral Plane ◽  
Content Type ◽  
Model Experiments ◽  
The Past ◽  
Air Inlet ◽  
Analysis Tools ◽  
Schlieren Photography ◽  
Fire Scene

Purpose The purpose of this paper is to analyze the variations in the neutral plane when a tall space with unsymmetrical openings is on fire. The neutral plane of the fire scene is an important index of a natural smoke exhaust system. The numerical simulation method and the Schlieren photography technique were used as analysis tools. The results of model experiments and numerical simulation were compared with each other to confirm the rationality of the conclusions. The results were to discuss the characteristics of various cases and showed that the neutral planes of the fire scene were not always horizontal. Design/methodology/approach The numerical simulation method and the Schlieren photography technique were used as analysis tools. The flow patterns of hot air in various cases were recorded using the flow visualization technique. In addition, the renowned simulation software, fire dynamics simulator (FDS), was used for case analysis. The Schlieren photography technique was used for 1/12.5 model experiments with six smokeless candles burned, and FDS was used for a numerical simulation. In terms of the case of unilateral vents, the exhaust efficiency was discussed when the exhaust vent and air inlet were located on the same side or different sides. Findings This study demonstrates that makeup air flowing in from the inlets and openings has a significant impact on the effectiveness of natural smoke exhaust systems. The results illustrated that the neutral planes were tilted in some cases. In some cases, the results showed that one side was the air inlet and the other side was the exhaust vent, even if the openings were at the same height in some cases. These phenomena have rarely been discovered or studied in the past. The exhaust efficiency was not always better when the vent was located in the rooftop. Originality/value This study analyzed the neutral plane of a fire scene using the common unsymmetrical opening spaces in the Taiwan region as an example. The phenomenon of non-horizontal neutral plane has rarely been studied in the past. The temperature of the discharged hot gas was low because of an efficient exhaust effect, which reduced the heat and smoke storage in the space. The results obtained by these two methods were consistent, and showed that the cases with the same opening area had different smoke extraction efficiencies, meaning the smoke extraction effect cannot be judged only by the opening areas.

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