Determining the aerodynamic drag of an automobile radiator with nonuniform cooling-air flow

2008 ◽  
Vol 28 (4) ◽  
pp. 307-310
Author(s):  
A. P. Petrov
Keyword(s):  
Aerodynamic Drag ◽  
Air Flow ◽  
Cooling Air Flow ◽  
Cooling Air

Investigation of Aerodynamic Wheel Designs on a Passenger Car at Different Cooling Air Flow Conditions

2011 ◽  
Author(s):  
Christoffer Landstro¨m ◽  
Lennart Lo¨fdahl
Keyword(s):  
Drag Reduction ◽  
Aerodynamic Drag ◽  
Air Flow ◽  
Flow Structures ◽  
Sustainable Mobility ◽  
Passenger Cars ◽  
Passenger Car ◽  
Flow Configurations ◽  
Cooling Air Flow ◽  
Cooling Air

Passenger cars represent the largest part of all means of personal transportation today. Thus, it is important to work towards reduced energy consumption of cars if a sustainable mobility is to be achieved. This involves many aspects of vehicle engineering; one of them being aerodynamics. This study focuses on aerodynamic drag and the contributions from the wheels at different cooling air flow configurations. Wheels and wheel housings are important for the overall aerodynamic drag on passenger cars. It has been shown that as much as 25% of the aerodynamic drag originates from these components. Therefore, it is desirable to understand the flow structures related to the wheels and wheel housings, and how they interact with other important flow regions. This paper presents an investigation of the effects of wheel designs on aerodynamic drag at different cooling air flow configurations on a sedan type passenger car. Comparisons between numerical simulations and wind tunnel measurements are made for some of the configurations as well. Several additional wheel configurations were investigated numerically to further investigate the flow structures at the front and rear wheels. The numerical results show that the effects of radial wheel covering varied noticeably with cooling air flow configuration. In two of the configurations this resulted in a net drag increase with closed cooling air inlets. The best configuration with closed cooling air inlets generated an overall drag reduction of 29 drag counts compared with the numerical baseline with open cooling air inlets. In addition to the obvious drag reduction of closing the cooling air inlets, the main reasons for the additional decrease was limiting the drag increase at the front stagnation region and positive interference effects along the underbody and vehicle base.

Analysis of Effect of Advanced Technique Configurations on Overall Performance of High Bypass Turbofan Engine

2014 ◽  
Author(s):  
Liu Jian Jun
Keyword(s):  
Air Flow ◽  
Engine Performance ◽  
Performance Model ◽  
Direct Drive ◽  
Nozzle Throat ◽  
Advanced Technique ◽  
Turbofan Engine ◽  
Overall Performance ◽  
Cooling Air Flow ◽  
Cooling Air

An analytical study was undertaken using the performance model of a two spool direct drive high BPR 300kN thrust turbofan engine, to investigate the effects of advanced configurations on overall engine performance. These include variable bypass nozzle, variable cooling air flow and more electric technique. For variable bypass nozzle, analysis on performance of outer fan at different conditions indicates that different operating points cannot meet optimal performance at the same time if the bypass nozzle area kept a constant. By changing bypass nozzle throat area at different states, outer fan operating point moves to the location where airflow and efficiency are more appropriate, and have enough margin away from surge line. As a result, the range of variable area of bypass nozzle throat is determined which ensures engine having a low SFC and adequate stability. For variable cooling airflow, configuration of turbine cooling air flow extraction and methodology for obtaining change of cooling airflow are investigated. Then, base on temperature analysis of turbine vane and blade and resistance of cooling airflow, reduction of cooling airflow is determined. Finally, using performance model which considering effect of cooling air flow on work and efficiency of turbine, variable cooling airflow effect on overall performance is analyzed. For more electric technique, the main characteristic is to use power off-take instead of overboard air extraction. Power off-take and air extraction effect on overall performance of high bypass turbofan engine is compared. Investigation demonstrates that power offtake will have less SFC.

Numerical and Experimental Methods to Investigate Cooling Air Flow in the Construction Machinery's Engine Compartment

2000 ◽  
Author(s):  
Toshikazu Nakanishi ◽  
Sanshirou Shimoda ◽  
Nobuhiko Yamasaki ◽  
Yuzo Inokuchi ◽  
Tsuyoshi Takemoto ◽  
...  
Keyword(s):  
Air Flow ◽  
Experimental Methods ◽  
Engine Compartment ◽  
Cooling Air Flow ◽  
Cooling Air

Hot gas ingestion in chute rim seal clearance of gas turbine

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Xingyun Jia ◽  
Huaiyu Dong ◽  
Yuzhou Ming ◽  
Yue Wu ◽  
Lidong He
Keyword(s):  
Air Flow ◽  
Interaction Mechanism ◽  
Flow Characteristics ◽  
Internal Flow ◽  
Navier Stokes ◽  
Marginal Effect ◽  
Pressure Potential ◽  
Hot Gas ◽  
Cooling Air Flow ◽  
Cooling Air

Abstract The Reynolds-averaged Navier–Stokes (RANS) solver was used to calculate, using a test rig to verify the accuracy. The interaction mechanism between different sealed cooling air and gas ingestion at the rotor-stator cavity and chute rim clearance has been investigated. Several groups of representative sealed cooling air flow were selected to explore the cooling efficiency, flow characteristics, tangential and radial velocity ratios in the cavity and the pressure potential field characteristics of trailing edge. The conclusions are obtained: the sealed cooling air flow rate has a significant marginal effect on the sealing effect. The gas ingestion behavior under the small sealed cooling air flow belongs to the disc cavity intrusion, and the intrusion and outflow regions at the of rim clearance are obviously divided into the intrusion characteristic section and the outflow characteristic section. The ingestion behavior under large sealed cooling air flow belongs to clearance ingestion, and the intrusion flow is limited to the chute rim clearance position, which cannot be further penetrated into the cavity. At this time, the clearance area and the cavity area become independent, and the gas ingestion characteristics depend more on the internal flow of the clearance and the vortex structure formed.

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