scholarly journals Analysis and Optimization of Truck Windshield Defroster

2020 ◽  
Vol 10 (16) ◽  
pp. 5671
Author(s):  
Zhilong He ◽  
Xide Qu ◽  
Lantian Ji ◽  
Weifeng Wu ◽  
Xiaolin Wang
Keyword(s):  
Main Part ◽  
Three Dimensional ◽  
Flow Characteristics ◽  
Flow Distribution ◽  
Medium Size ◽  
Average Pressure ◽  
Factors Affecting ◽  
Guide Plate ◽  
Simulation Results ◽  
Major Factors

Frosting and fogging of automobile windshields is a common problem that emerges in daily driving. It is important and essential to quickly and completely defrost the windshield for safety purposes. In this study, a three-dimensional mathematical model was applied to investigate the flow distribution and flow characteristics on the windshield of a medium-size Model N800 truck. The simulation results were first compared with experimental data. The results showed that the simulation model could reliably predict the defrosting performance on the windshield. This model was then used to optimize the design of the defrosting duct that comprised the main part of the defroster. It was found that the guide plate and outlet position of the defrosting duct were the two major factors affecting the defrosting performance. Therefore, the guide plate was first optimized and the defrosting performance was analyzed. The results showed that the average pressure loss dropped by 21.56%, while the defrosting efficiency at the front white zone was improved to 89%. The position of the outlet of the airflow was further studied. The results showed that the defrosting efficiency at the front zone could be further improved to 99%.

FINITE ELEMENT SIMULATION OF PORE CLOSING DURING CYLINDER UPSETTING

2008 ◽  
Vol 22 (31n32) ◽  
pp. 5768-5773 ◽  
Author(s):  
MIN CHEOL LEE ◽  
SUNG MIN JANG ◽  
JU HYUN CHO ◽  
MAN SOO JOUN
Keyword(s):  
Metal Forming ◽  
Effective Strain ◽  
Three Dimensional ◽  
Strong Relationship ◽  
Longitudinal Section ◽  
Factors Affecting ◽  
Dimensional Precision ◽  
Cylinder Diameter ◽  
Element Simulation ◽  
Major Factors

Three-dimensional precision simulation of pore closing during cylinder upsetting is carried out in this paper. A matrix of pores on the longitudinal section of a cylindrical material is traced at the same time. Various ratios of pore-to-cylinder diameter are tested to reveal their effect on the pore closing phenomena. Hydrostatic pressure and effective strain as well as the order of pore closing are investigated in detail to find out major factors affecting pore closing. It is shown that the effective strain has a strong relationship with the pore closing phenomena and that the finishing time of pore closing increases as the ratio of pore-to-cylinder diameter increases but that the pore size effect becomes negligible if the ratio exceeds a critical value. An intelligent metal forming simulator AFDEX 3D is used.

I-880 Field Experiment: Analysis of Incident Data

1997 ◽  
Vol 1603 (1) ◽  
pp. 72-79 ◽  
Author(s):  
Alexander Skabardonis ◽  
Karl F. Petty ◽  
Robert L. Bertini ◽  
Pravin P. Varaiya ◽  
Hisham Noeimi ◽  
...  
Keyword(s):  
Field Experiment ◽  
Response Times ◽  
Flow Characteristics ◽  
Supplementary Information ◽  
Freeway Traffic ◽  
Factors Affecting ◽  
Probe Vehicle ◽  
Before And After ◽  
Dispatch System ◽  
Major Factors

The I-880 field experiment has produced one of the largest data bases on incidents and freeway traffic-flow characteristics ever compiled. Field data on incidents were collected through observations of probe-vehicle drivers before and after the implementation of freeway service patrols (FSPs) over a freeway section. Supplementary information was collected from the California Highway Patrol’s computer-aided dispatch system, FSPs, and tow-truck company logs. The incident patterns are described and the major factors affecting incident frequency and duration are identified. FSPs significantly reduced the response times but did not have a significant effect on the duration of all incidents.

Research on V-Groove Angle of Rotated Dual-Plates Lapping Machine

2010 ◽  
Vol 37-38 ◽  
pp. 1125-1129 ◽  
Author(s):  
Ju Long Yuan ◽  
Wei Feng Yao ◽  
Qian Fa Deng ◽  
Bing Hai Lv
Keyword(s):  
Angular Velocity ◽  
Three Dimensional ◽  
Dimensional Model ◽  
Three Dimensional Model ◽  
Factors Affecting ◽  
Simulation Results ◽  
Lapping Machine

The V-groove angle of the machine is considered as one of important factors affecting the processing and the ball’s precision. To study its effect, the three-dimensional model of RDP lapping machine is built and a series of simulations at different V-groove angles are carried out, using the software ADAMS based on the RDP principle. The influence of three parameters including spin angle, spin angular velocity and revolution angular velocity are discussed by observing and analyzing the simulation results. It is concluded that some optimized V-groove angles can improve the sphericity of ball; some ones can induce the balls to move back and roll during some periods of the processing.

Three-Dimensional Numerical Analysis of Gas Flow and Heat Transfer in SOFCs With Honeycomb-Like Channels

2010 ◽  
Author(s):  
Yuan Huang ◽  
Weiguo Wang ◽  
Jinliang Yuan ◽  
Bengt Sunden
Keyword(s):  
Heat Transfer ◽  
Pressure Drop ◽  
Diffusion Layer ◽  
Gas Flow ◽  
Stokes Equations ◽  
Rectangular Channel ◽  
Three Dimensional ◽  
Flow Distribution ◽  
Gas Diffusion ◽  
Factors Affecting

Design of advanced flow channels in bipolar plates is one of the key factors affecting SOFC stack and system performance. Various transport phenomena occurring in SOFCs with conventional interconnects with rib- or serpentine channels, etc, have been extensively studied. In this paper new designed channels are proposed and evaluated numerically by computational software. The investigated geometry consists of two computational domains: a porous anode layer and interconnect. The latter one serves as gas distribution for hydrogen or air in SOFCs. Compared with conventional designs, the configuration of interconnect having honeycomb structures is different. Such unique channels lead to gas flow in many directions, and gas flow distribution and pressure drop are significantly different from those in conventional designs. This simulation employs the Navier-Stokes equations for the gas flow in the channels, and the Darcy model in the porous layer. Combined gas and heat transfer in the channels and the porous gas diffusion layer, permeation across the interface are analyzed by a fully three-dimensional code in this paper. All the governing equations are solved utilizing the commercial code COMSOL. The velocity field, the distribution of hydrogen in the channels, the fraction of the hydrogen entering the anode diffusion layer, and the pressure drop are predicted and presented. Also, the friction factor of the unique design is compared with that of the rectangular channel. The numerical results and findings from this study are important for optimizing the flow fields, decreasing the cost of experiments and designing of the channels.

Liquid Flow Characteristics in Microchannels

2011 ◽  
Vol 130-134 ◽  
pp. 1484-1490
Author(s):  
Yan Feng Liu ◽  
Hong Wei Li ◽  
Jing Wei Zhang ◽  
Jin Xue
Keyword(s):  
Heat Transfer ◽  
Experimental Data ◽  
Fluid Flow ◽  
Three Dimensional ◽  
Flow Characteristics ◽  
Simulation Methods ◽  
Dimensional Model ◽  
Three Dimensional Model ◽  
Simulation Results ◽  
Poiseuille Number

A three-dimensional model was developed to simulate the laminar flow and convective heat transfer in rectangular silicon microchannels，which have hydraulic diameter of 95.3，92.3 ,85.8 , 80 and 75μm respectively．The rationality of the simulation methods and results were validated by comparing with experimental data. The simulation results indicate that the aspect ratio has a significant impact on the Poiseuille number. Conventional fluid flow theory is fit for researching the fluid flow in microchannels, Po is a constant that is not dependent on the Reynolds number.

Flow Field Analysis of the Reactor Coolant Pump Internal Cooling Circulation

2017 ◽  
Author(s):  
Jie Qin ◽  
Qingmu Xu ◽  
Junkai Yuan ◽  
Kun Cai
Keyword(s):  
Heat Transfer ◽  
Flow Field ◽  
Three Dimensional ◽  
Flow Characteristics ◽  
Flow Distribution ◽  
Internal Cooling ◽  
Shaft Seal ◽  
Flow Area ◽  
Coolant Pump ◽  
Reactor Coolant

Reactor coolant pump (RCP) is one of the most critical devices in third generation of pressurized water reactor nuclear power plant. EMD shield pump and KSB wet winding pump are two representative kinds of RCPs without complex shaft seal system. Due to cancellation of shaft seal system, the entire rotors (including the flywheel) are immersed in the coolant. The losses in RCPs take one third of the total power including rotation loss caused by rotor in the water, electromagnetic loss in the shielding sleeve,the heat transferred through high temperature coolant, and heat generated by bearing.Because of the losses listed above, bearing and winding are heated,and the losses make temperature rise. in order to ensure that the motor is working properly at low temperatures, the company EMD and KSB design the RCP internal cooling circulation which brings the heat out to ensure the normal operation of the RCPs. The RCP internal cooling circulation includes inlet flow area, auxiliary impeller, thrust bearing, the lower flywheel, motor can, upper radial bearing, upper flywheel, outlet flow area, and external heat exchanger,etc. Flow characteristics in every flow path determine the flow distribution and heat transfer, and the flow distribution determines whether the cooling performance of RCP internal cooling circulation meets the requirements. In order to control operating temperature of motor and bearing, and to optimize heat transfer, adjusting the size of flow area and changing the flow characteristics arecritical. flow field and temperature field in RCP internal cooling circulation need overall analysis. Flow distribution can be obtained theoretically through the calculation of an overall three-dimensional model.But on the one hand, the calculation time is long due to a complex three-dimensional model with a large quantity of grids, on the other hand, it is easier to casue errors in local processing and the errors are difficult to find or correct. For rapid analysis and optimization of flow and heat transfer in RCP internal cooling circulation, ensure the motor winding and bearing operate at an appropriate temperature, the local characteristics of RCP internal cooling circulation are studied, one-dimensionalanalysis method of RCP internal cooling circulation is developed. This one-dimensional analysis method can be used to predict the flow distribution of each part of RCP internal cooling circulation according to change of the channel geometry parameters, key dimensions, boundary conditions and rotor speed. The geometric parameters are optimized by analyzing the flow distribution, and the purpose of design guidance are achieved.

scholarly journals Drag Reduction Mechanism of Viscoelastic Slick-Water Fracturing Fluid in Tortuous and Rough Fractures

Geofluids ◽  
2021 ◽  
Vol 2021 ◽  
pp. 1-11
Author(s):  
Zhiyu Liu ◽  
Fan Fan ◽  
Donghang Zhang ◽  
Yang Li ◽  
Yuan Li ◽  
...  
Keyword(s):  
Molecular Weight ◽  
Drag Reduction ◽  
Flow Rate ◽  
Three Dimensional ◽  
Flow Characteristics ◽  
Flow Rule ◽  
Mechanism Analysis ◽  
Reduction Mechanism ◽  
Fracturing Fluid ◽  
Factors Affecting

Slick-water can effectively reduce the flow drag of fracturing fluid. Many studies have focused on the drag reduction performance of slick-water in wellbore and perforation, but there has been little research on drag reduction characteristics in fracture flow. In this paper, a new visualization experiment system is used to simulate real fracture. The fracture surface is produced through actual triaxial hydraulic fracturing and is copied by a three-dimensional printer using resin material to maintain its shape feature. In comparing the experimental results, it was found that the main factors affecting drag reduction in a fracture are the relative molecular weight and the added concentration. Unlike the flow rule of the drag reducer in a pipeline, when the concentration is greater than 0.10%, a negative DR effect begins to appear. The influence of molecular weight is related to the flow stage; the increasing of molecular weight causes a reduction in DR effect when the flow rate is 0.24 m/s. However, the flow rate exceeds 0.5 m/s; drag reducers with higher molecular weight demonstrate better drag reduction performance. The drag reduction mechanism analysis in fractures was obtained from visualization observations, and the flow characteristics of fluid were characterized by using tracking particles. Drag reduction effect occurs mainly on the surface of the fractures in contrast to near the centre of the flow channel. This research can provide a reference for the experimental study on drag reduction in fractures and is of great significance to the optimization and improvement of drag reducing agent.

Experimental and Simulation Research on Flow Characteristics of SCR System in a 100MW Power Station

2014 ◽  
Vol 1051 ◽  
pp. 920-926
Author(s):  
Qian Jun Li ◽  
Dong Ping Zhang ◽  
Fang Zhang ◽  
Xian Feng Liu
Keyword(s):  
Concentration Field ◽  
Flow Characteristics ◽  
Test Plant ◽  
Simulation Research ◽  
Guide Plate ◽  
Practical Engineering ◽  
Simulation Results ◽  
Scr System ◽  
Better Than ◽  
Good Agreement

This work try to optimize the flow field and concentration field of SCR system. Firstly, the original SCR system is simulated by Fluent and two kinds of guide plates are utilized. The simulation results show that the straight guide plate is slightly better than curve guide plate. The relatively standard deviation of velocity and concentration fields and pressure drop agree with the design rules. To verify the simulation results, a 1:10 scale cold plexiglass test plant is established and this plant is simulated correspondingly. The simulation results are in good agreement with experimental results. So the simulation results of original SCR system are credibly and can guide the practical engineering.

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