scholarly journals Prediction of HAVC Cool-Down Performance inside a Minibus Passenger Cabin Using CFD and Its Experimental Validation.

2019 ◽  
Vol 11 (01) ◽  
pp. 47-56
Author(s):  
Nikhil Mhetre ◽  
Suraj Sathyanarayan ◽  
Manoj Diwan ◽  
Siddharth Kumar ◽  
Dattatray Hulwan
Keyword(s):  
Wind Tunnel ◽  
Heat Load ◽  
Cfd Simulation ◽  
Wind Tunnel Testing ◽  
Cfd Model ◽  
Simulation Methodology ◽  
Computational Fluid Dynamics Cfd ◽  
Climatic Wind Tunnel ◽  
Passenger Cabin ◽  
Good Agreement

Now with more time spent by people while travelling and increasing mobility, providing passengers with a thermally comfortable experience are one of the important targets of any bus manufacturer. Conversely, comprehensive assessment through Climatic Wind Tunnel testing is costly and not possible during early stages of vehicle design. The aim of this work has been to develop a simplified simulation methodology to model the Minibus passenger cabin for cool down test. This study presents a methodology for predicting Heating, Ventilation and Air Conditioning (HVAC) cool-down performance inside Minibus cabin using Computational Fluid Dynamics (CFD) simulation to revise the HVAC duct design and parametric optimization in order to ensure thermal comfort of occupant. Heat Load is calculated analytically and has been considered in the CFD model and occupant heat load is considered as per ASHRAE standard. CFD simulation predicted the temperature and velocity distribution inside passenger cabin. Simulated cool-down results were found to be in good agreement with the experimental results. CFD cool-down prediction is useful in order to reduce time and costs related to climatic wind tunnel and road tests. Validated CFD model is used to study the effect of air flow on cool-down performance.

scholarly journals Transient 3D CFD Simulation of a Stationary Vane, Oil Free, Rotary Compressor

2019 ◽  
Vol 63 (4) ◽  
pp. 308-318 ◽  
Author(s):  
Balázs Farkas ◽  
Jenő Miklós Suda
Keyword(s):  
Cfd Simulation ◽  
Piston Compressor ◽  
Working Fluid ◽  
Rotary Compressor ◽  
Heat Sources ◽  
Cfd Model ◽  
Cfd Simulations ◽  
Computational Fluid Dynamics Cfd ◽  
Rolling Piston ◽  
Good Agreement

The evaluation of a newly designed oil-free rotary compressor is presented based on transient 3D Computational Fluid Dynamics (CFD) simulations. The simulations are performed at low compression ratios and low pressure ratios and low rotational speeds. To place the results into context, the data presented in related literature was processed and summarized. The methods related to the CFD model of the newly designed compressor were developed, summarized and evaluated. The accessed CFD data are in good agreement with the results of the former rolling piston compressor related investigations. The oil free operation prevents the contamination of the working fluid from lubricant. Since the compressor is planned to work in open cycle within the sensitive environment of thermal heat sources contamination free operation has to be accomplished. However, oil-free operation also results in significantly lower performance based on the modelling results.

scholarly journals CFD Simulation Model of Salt Wedge Propagation

2022 ◽  
Vol 28 (1) ◽  
pp. 76-85
Author(s):  
Aya kh. Shaheed ◽  
Riyadh Z. Azzubaidi
Keyword(s):  
Numerical Simulation ◽  
Simulation Model ◽  
Cfd Simulation ◽  
Laboratory Data ◽  
Cfd Model ◽  
Salt Wedge ◽  
Laboratory Results ◽  
Computational Fluid Dynamics Cfd ◽  
Bed Slope ◽  
Good Agreement

This study aims to numerically simulate the flow of the salt wedge by using computational fluid dynamics, CFD. The accuracy of the numerical simulation model was assessed against published laboratory data. Twelve CFD model runs were conducted under the same laboratory conditions. The results showed that the propagation of the salt wedge is inversely proportional to the applied freshwater discharge and the bed slope of the flume.  The maximum propagation is obtained at the lowest discharge value and the minimum slope of the flume. The comparison between the published laboratory results and numerical simulation shows a good agreement. The range of the relative error varies between 0 and 16% with an average of 2% and a root mean square error of 0.18. Accordingly, the CFD software is quite valid to simulate the propagation of the salt wedge. 

scholarly journals Optimal thermal sensors placement based on indoor thermal environment characterization by using CFD model

2021 ◽  
Vol 19 (3) ◽  
pp. 628-641
Author(s):  
F Faridah ◽  
Sentagi Utami ◽  
Ressy Yanti ◽  
S Sunarno ◽  
Emilya Nurjani ◽  
...  
Keyword(s):  
Euclidean Distance ◽  
Cfd Simulation ◽  
Thermal Environment ◽  
Thermal Characteristics ◽  
Data Sets ◽  
Cfd Model ◽  
Outdoor Climate ◽  
Computational Fluid Dynamics Cfd ◽  
Maximum Root ◽  
Optimum Sensor

This paper discusses an analysis to obtain the optimal thermal sensor placement based on indoor thermal characteristics. The method relies on the Computational Fluid Dynamics (CFD) simulation by manipulating the outdoor climate and indoor air conditioning (AC) system. First, the alternative sensor's position is considered the optimum installation and the occupant's safety. Utilizing the Standardized Euclidean Distance (SED) analysis, these positions are then selected for the best position using the distribution of the thermal parameters' values data at the activity zones. Onsite measurement validated the CFD model results with the maximum root means square error, RMSE, between both data sets as 0.8°C for temperature, the relative humidity of 3.5%, and an air velocity of 0.08m/s, due to the significant effect of the building location. The Standardized Euclidean Distance (SED) analysis results are the optimum sensor positions that accurately, consistently, and have the optimum % coverage representing the thermal condition at 1,1m floor level. At the optimal positions, actual sensors are installed and proven to be valid results since sensors could detect thermal variables at the height of 1.1m with SED validation values of 2.5±0.3, 2.2±0.6, 2.0±1.1, for R15, R33, and R40, respectively.

Functional Prototyping and Tooling of FDM Additive Manufactured Parts

2014 ◽  
Author(s):  
Farzad Rayegani ◽  
Godfrey C. Onwubolu ◽  
Attila Nagy ◽  
Hargurdeep Singh
Keyword(s):  
Fluid Dynamics ◽  
Additive Manufacturing ◽  
Wind Tunnel ◽  
Wind Tunnel Testing ◽  
Tool Paths ◽  
Aerodynamic Properties ◽  
Vacuum Forming ◽  
Computational Fluid Dynamics Cfd ◽  
Functional Prototype ◽  
Tunnel Testing

In this paper, we present two additive manufacturing applications: (1) vacuum forming tooling using AM; (2) rocket functional prototype using AM for computational fluid dynamics (CFD) and wind-tunnel testing. The first application shows how additive manufacturing (AM) facilitates the manufacture of vacuum formed parts, which allows such parts to be easily produced especially in the manufacturing sector. We show how combining the advantages of the CAD and FDM technology, vacuum forming can be completed quickly, efficiently and cost effectively. The paper shows that using modified build parameters, the tools FDM creates can be inherently porous, which eliminates the time needed for drilling vent holes that are necessary for other vacuum forming tools, while improving part quality with an evenly distributed vacuum draw. Using SolidWorks CAD software, the model of the tool is created. The STL file is exported to the Insight software, and we present how the Tool Paths Custom Group feature is applied to optimize the tool-paths file and then sent to the FDM system that prints the tooling from ABS engineering thermoplastic. The tooling is then used in the Formech 686 manual vacuum forming machine to produce the vacuum formed part. The second application shows how additive manufacturing (AM) has been applied to producing functional model for wind–tunnel testing, as well as providing computational fluid dynamics (CFD) tool for comparing results obtained from the wind-tunnel testing. The present work is focused on applications of FDM technology for manufacturing wind tunnel test models. The CAD model of a rocket was analyzed for its aerodynamic properties and its functional prototype produced using AM for use in wind–tunnel testing so as to verify and tune the aerodynamic properties. Initial wall conditions were defined for the rocket in terms of the air velocity. The flow simulation was carried out and the goals examined are the velocity and pressure fields around the rocket model. The paper examines some practical issues that arise between how the model geometry for CDF process differs from that that of the FDM process. Consequently, we show that AM-based fused deposition modeling (FDM) technology is faster, less expensive and more efficient than traditional manufacturing processes for vacuum forming and for rapid prototyping of function models for wind-tunnel applications.

Verification and Validation of a Detonation Computational Fluid Dynamics Model

2016 ◽  
Vol 366 ◽  
pp. 40-46
Author(s):  
Rui Li Wang ◽  
Xiao Liang ◽  
Wen Zhou Lin ◽  
Xue Zhe Liu ◽  
Yun Long Yu
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Cfd Simulation ◽  
Verification And Validation ◽  
Cfd Model ◽  
Dynamics Model ◽  
Computational Fluid Dynamics Model ◽  
Primary Means ◽  
Computational Fluid Dynamics Cfd ◽  
2D Space

Verification and validation (V&V) are the primary means to assess the accuracy and reliability in computational fluid dynamics (CFD) simulation. V&V of the multi-medium detonation CFD model is conducted by using our independently-developed software --- Lagrangian adaptive hydrodynamics code in the 2D space (LAD2D) as well as a large number of benchmark testing models. Specifically, the verification of computational model is based on the basic theory of the computational scheme and mathematical physics equations, and validation of the physical model is accomplished by comparing the numerical solution with the experimental data. Finally, some suggestions are given about V&V of the detonation CFD model.

The Simulation and Inspection for the Starting Phenomenon of Slit Coating Process on Glass Substrate

2011 ◽  
Vol 5 (2) ◽  
pp. 190-194
Author(s):  
Ta-Hsin Chou ◽  
◽  
Wen-Hsien Yang ◽  
Kuei-Yuan Cheng ◽  
Yu-Chen Chang ◽  
...  
Keyword(s):  
Feed Rate ◽  
Glass Substrate ◽  
Cfd Simulation ◽  
Fluid Flows ◽  
Ccd Camera ◽  
Cfd Model ◽  
Liquid Feed ◽  
Experimental Parameters ◽  
Computational Fluid Dynamics Cfd ◽  
Horizontal Moving

We developed a two-dimensional Computational Fluid Dynamics (CFD) model of a slit nozzle and coating for photoresist, using the Volume Of Fluid (VOF) to calculate the transient free surface. Parameters studied in simulation, including contact angle, liquid feed rate, slit gap, and coating gap. Simulation results yielded information on operation and buildup conditions, enabling us to examine microscopic fluid flows. Experiments used a slit coater (ITRI) having a slit nozzle 370 mm wide and a 100 µm slit gap, and set on a vertical moving table. A glass substrate was fixed on a horizontal moving table by a vacuum pump. Photoresist is pumped from a tank to the slit nozzle by a plunger. During coating, a CCD camera facing the slit gap imaged coating conditions. Experimental parameters studied included substrate speed, coating gap, and photoresist feed rate. The substrate was operated at 10 to 20 mm/second, the coating gap was set at 100 µm, and the photoresist feed rate was from 0.4 to 0.8 ml. Simulation and experimental results confirmed that CFD simulation was possible in designing the slit nozzle and preverifying coating. Photoresist coating was possible below 1.5 µm thick with 5%uniformity.

Manufacturing and Computational Fluid Dynamics Modeling of a Patient-Specific Fistula Model

2017 ◽  
Author(s):  
Yang Liu ◽  
Yihao Zheng ◽  
John Pitre ◽  
William Weitzel ◽  
Joseph Bull ◽  
...  
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Patient Specific ◽  
Cfd Model ◽  
Dynamics Modeling ◽  
Computational Fluid Dynamics Modeling ◽  
Computational Fluid Dynamics Cfd ◽  
Particle Imaging ◽  
Venous Wall ◽  
Good Agreement

Arteriovenous fistula is the joining of an artery to a vein to create vascular access for dialysis. The failure or maturation of fistula is affected by the vessel wall shear stress (WSS), which is difficult to measure in clinic. A computational fluid dynamics (CFD) model was built to estimate WSS of a patient-specific fistula model. To validate this model, a silicone phantom was manufactured and used to carry out a particle imaging velocimetry (PIV) experiment. The flow field from the PIV experiment shows a good agreement with the CFD model. From the CFD model, the highest WSS (40 Pa) happens near the anastomosis. WSS in the vein is larger than that in the artery. WSS on the outer venous wall is larger than that on the inner wall. The combined technique of additive manufacturing, silicone molding, and CFD is an effective tool to understand the maturation mechanism of a fistula.

Investigation of Pressure Dependent Thermal Contact Resistance between Silver Metallized SiC Chip and DBC Substrate

2015 ◽  
Vol 821-823 ◽  
pp. 452-455 ◽  
Author(s):  
Zsolt Toth Pal ◽  
Ya Fan Zhang ◽  
Ilja Belov ◽  
Hans Peter Nee ◽  
Mietek Bakowski
Keyword(s):  
Heat Transfer ◽  
Contact Resistance ◽  
Thermal Contact Resistance ◽  
Cfd Simulation ◽  
Thermal Contact ◽  
Cfd Model ◽  
Transfer Experiment ◽  
Transfer Path ◽  
Computational Fluid Dynamics Cfd ◽  
Pressure Independent

– Thermal contact resistances between a silver metallized SiC chip and a direct bonded copper (DBC) substrate have been measured in a heat transfer experiment. A novel experimental method to separate thermal contact resistances in multilayer heat transfer path has been demonstrated. The experimental results have been compared with analytical calculations and also with 3D computational fluid dynamics (CFD) simulation results. A simplified CFD model of the experimental setup has been validated. The results show significant pressure dependence of the thermal contact resistance but also a pressure independent part.

Design and Production of Wind Tunnel Testing Models with Selective Laser Sintering Technology Using Glass-Reinforced Nylon

2006 ◽  
Vol 532-533 ◽  
pp. 653-656 ◽  
Author(s):  
Saeed Daneshmand ◽  
R. Adelnia ◽  
S. Aghanajafi
Keyword(s):  
Wind Tunnel ◽  
Selective Laser Sintering ◽  
Aerodynamic Characteristics ◽  
Laser Sintering ◽  
Cnc Machining ◽  
Wind Tunnel Testing ◽  
The Cost ◽  
Force Data ◽  
Good Agreement ◽  
Tunnel Testing

In this study, the ability of Selective Laser Sintering (SLS) Technology for production of wind tunnel testing models are evaluated. It has been undertaken to determine the suitability of the Model constructed with SLS method in subsonic and transonic wind tunnel testing. Two models were evaluated in this study. The first model was fabricated from aluminum 5086-H32 by a CNC machining technique. The other model had the same section but was fabricated by the selective laser sintering (SLS) process. Aerodynamic characteristics and times as well as costs of both models were measured in 0.3 to 1.2 Mach and the results were compared. The longitudinal aerodynamic data and the normal force data obtained from SLS model showed good agreement with data obtained from the aluminum model. The greatest difference in the aerodynamic data between two models is the total axial force. The time and the cost of production are considerably reduced with use of SLS model.

Frost Growth CFD Model of an Integrated Active Desiccant Rooftop Unit

2007 ◽  
Author(s):  
Patrick Geoghegan ◽  
Andrei Petrov ◽  
Edward Vineyard ◽  
Randall Linkous ◽  
Abdolreza Zaltash
Keyword(s):  
Cfd Simulation ◽  
Vapor Compression ◽  
Cfd Model ◽  
Outdoor Air ◽  
Transient Model ◽  
Space Cooling ◽  
Heat Transfer Capacity ◽  
Computational Fluid Dynamics Cfd ◽  
Heating Loads ◽  
Frost Growth

A frost growth model is incorporated into a Computational Fluid Dynamics (CFD) simulation of a heat pump by means of a user-defined function in a commercial CFD code. The transient model is applied to the outdoor section of an Integrated Active Desiccant Rooftop (IADR) unit in heating mode. IADR is a hybrid vapor compression and active desiccant unit capable of handling 100% outdoor air (dedicated outdoor air system) or as a total conditioning system, handling both outdoor air and space cooling or heating loads. The predicted increase in flow resistance and loss in heat transfer capacity due to frost build-up are compared to experimental pressure drop readings and thermal imaging. The purpose of this work is to develop a CFD model that is capable of predicting frost growth, a potentially valuable tool in evaluating the effectiveness of defrost-on-demand cycles.

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