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Stall Mitigation and Lift Enhancement of NACA 0012 with Triangle-Shaped Surface Protrusion at a Reynolds Number of 105

SAE International Journal of Aerospace

University of Petroleum and Energy Studies, India-Aslesha Bodavula, Rajesh Yadav, Ugur Guven
  • Journal Article
  • 01-12-02-0007
Published 2019-11-22 by SAE International in United States
Transient numerical simulations are conducted over a NACA 0012 airfoil with triangular protrusions at a Reynolds number (Re) of 100000 using the γ-Reθ transition Shear Stress Transport (SST) turbulence model. Protrusions of heights 0.5%c, 1%c, and 2%c are placed at one of the three locations, viz, the leading edge (LE), 5%c on the suction surface, and 5%c on the pressure surface, while the angle of attack (AOA) is varied between 0° and 20°. Results obtained from the time-averaged solution of the unsteady Navier-Stokes equation indicate that the smaller protrusion placed at 5%c on the suction surface improves the post-stall lift coefficient by up to 59%, without altering the pre-stall characteristics. The improvement in time-averaged lift coefficients comes with enhanced flow unsteadiness due to vigorous vortex shedding. For a given protrusion height, the vortex shedding frequency decreases as the AOA is increased, while the amplitude of fluctuations in lift coefficient increases as the protrusion height is increased or as the AOA is increased. Nevertheless, mitigation of static stall phenomena is observed for most configurations investigated, and…
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Self-Sensing, Lightweight and High Modulus Carbon Nanotube Composites for Improved Efficiency and Safety of Electric Vehicles

NoPo Nanotechnologies India Pvt Ltd.-Gadhadar Changalaraya Reddy, Aparna Allannavar
  • Technical Paper
  • 2019-28-2532
Published 2019-11-21 by SAE International in United States
Carbon Composites (CFRP) have been touted to be an essential component of future automobiles due to their mechanical properties and lightweight. CFRP has been adopted successfully for secondary and primary structures in Aerospace industry. In Automobiles, they are incorporated in models like the BMW i-series. CFRP suffers from 2 major problems. Delamination of Composites leads to catastrophic and rapid failure which could be dangerous in passenger vehicles. Delamination occurs whenever there is a shock on the composite. Secondly, Composites need regular expensive maintenance to ensure that the material is intact and will not compromise passenger safety. Carbon Nanotubes in composites have shown a substantial increase in delamination resistance. A 0.1wt% addition of HiPCO® Single-walled Carbon Nanotube provides both self-sensing and improved fracture resistance. Here we report results of our work with NoPo HiPCO® Nanotubes with small amounts of Iron. 6K Carbon fiber was used as the fiber reinforcement. NoPo HiPCO® Nanotubes were reinforced in the Epoxy system by sonication. HiPCO® Nanotubes were produced using standard parameters. The coupons of CENCE composite were made using VARTM…
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Impact of Wheel-Housing on Aerodynamic Drag and Effect on Energy Consumption on an Electric Bus Body

ARAI Academy-Amitabh Das, Yash Jain
Automotive Research Association of India-Mohammad Rafiq Agrewale, Kamalkishore Vora
  • Technical Paper
  • 2019-28-2394
Published 2019-11-21 by SAE International in United States
Role of wheel and underbody aerodynamics of vehicle in the formation of drag forces is detrimental to the fuel (energy) consumption during the course of operation at high velocities. This paper deals with the CFD simulation of the flow around the wheels of a bus with different wheel housing arrangements. Based on benchmarking, a model of a bus is selected and analysis is performed. The aerodynamic drag coefficient is obtained and turbulence around wheels is observed using ANSYS Fluent CFD simulation for different combinations of wheel-housing- at the front wheels, at the rear wheels and both in the front and rear wheels. The drag force is recorded and corresponding influence on energy consumption of a bus is evaluated mathematically. A comparison is drawn between energy consumption of bus body without wheel housing and bus body with wheel housing. The result shows a significant reduction in drag coefficient and fuel consumption.
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Analysis Of GaN Based BLDC Motor Drive For Automotive Application

Sudhanshu Telrandhe-Sudhanshu Harish Telrandhe
  • Technical Paper
  • 2019-28-2471
Published 2019-11-21 by SAE International in United States
Objective Automotive sector is rapidly moving towards electric vehicle. BLDC motor is gaining popularity in the field of electric vehicle due to its high torque to weight ratio and simple control. In this paper we will focus on Switching loss characterization of 3 kW GaN based BLDC drive for electric vehicle. To improve efficiency of drive gallium-nitride based power transistor is used instead of Si MOSFET. GaN devices enable the design of inverter at higher frequencies with improved power density and efficiency as compared to traditional Si MOSFETs. Methodology In this paper commercially available GaN devices compared with Si MOSFETs. The power devices, which are selected for the performance comparison, are EPC2022 GaN by EPC, GS61008P GaN by Gan System and SiDR668DP Si MOSFET by Vishay. The Switching losses analytically predicted in MATHCAD tool and then compared with SPICE simulation losses. Double pulse test circuit is used to find out power losses of power transistors. This double pulse test carried out for two different GaN devices from two manufacturers and one traditional Si mosfet device…
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Aerodynamic analysis of commercial vehicle using active vortex generators concept

ARAI Academy-Saurabh Jayant Kulkarni, Kamalkishore Vora
Automotive Research Association of India-Mohammad Rafiq Agrewale
  • Technical Paper
  • 2019-28-2409
Published 2019-11-21 by SAE International in United States
Any physical body being propelled through the air has drag associated with it. Drag will be created on the surface of the vehicle due to the flow separation at the rear end. In aerodynamics the flow separation can often result in increased drag particularly pressure drag, to delay the flow separation, the vortex generators are used on the roof end of the vehicle just before the point of flow separation. The objective of this project is to perform aerodynamic analysis of commercial vehicle using active vortex generators concept. First, the aerodynamic analysis of a baseline commercial vehicle model is performed and same is validated with the scaled model by using a wind tunnel test. Further analysis has been done by using active vortex generators concept with variation of angle of attacks for vehicle speed of 50, 70, 90 kmph. Also, analysis has been carried out for six different yaw angles. The simulation is carried out with the use of ANSYS Fluent. The simulation result shows the significant drag coefficient reduction of the commercial vehicle with…
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Effect of Tyre Inflation Pressure on Rolling Resistance : Comparing the Values of Coefficient of Rolling Resistance and Rolling Resistance at Variable Tyre Inflation Pressure

International Centre for Automotive Technology-Siddharth Tripathi, Amit Kumar Karwal, Mukund Mishra, Dushyant Wazir
  • Technical Paper
  • 2019-28-2415
Published 2019-11-21 by SAE International in United States
1Rolling resistance, is nothing but the rolling drag, is the force resisting the motion when a body rolls on a surface. It is mainly caused by non-elastic effects; that is, not all the energy needed for deformation of the wheel, roadbed, etc. It is recovered when the pressure is removed, in the form of hysteresis losses and permanent deformation of the tyre surface. So, the rolling resistance contributes to the deformation of roadbed as well as tyre surface of the vehicle. Factors contributing in rolling resistance are tyre inflation pressure, wheel diameter, speed, load on wheel, surface adhesion, sliding and relative micro-sliding between the surfaces of contact. In this concerned paper we are significantly working on effect of tyre inflation pressure on rolling resistance and taking all other factors constraint.
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Mold in Color Diamond White ASA Material for Automotive Exterior Application

Mahindra & Mahindra, Ltd.-Karthik Govindaraj, K V Balaji, Murukesan Vimalathithan, Gandhi Samir, Ladhe Rajesh
  • Technical Paper
  • 2019-28-2562
Published 2019-11-21 by SAE International in United States
In this paper, mold in color diamond white ASA material has been explored for front bumper grill, fender arch extension, claddings and hinge cover applications. Other than aesthetic requirements, these parts have precise fitment requirement under sun load condition in real world usage profile. Structural durability of the design was validated by virtual engineering. Part design and material combinations with better tooling design iterations were analyzed by using mold flow analysis. Complete product performances were validated for predefined key test metrics such as structural durability, thermal aging, cold impact, scratch resistance, and weathering criteria. This part met required specification. This mold in color ASA material-based parts has various benefits such as environmentally friendly manufacturing by eliminating environmental issues of coating, easily recycled, and faster part production because intended color achieved in one step during molding. Also, it lowers overall production energy footprint, less scrap with no secondary painting, and lower final part cost by eliminating secondary operations.
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Aerodynamic Analysis of a Passenger Car to Reduce Drag Using Active Grill Shutter and Active Air Dam

ARAI Academy-Raghav Tandon
Automotive Research Association of India-Mohammad Rafiq Agrewale, Kamalkishore Vora
  • Technical Paper
  • 2019-28-2408
Published 2019-11-21 by SAE International in United States
Active aerodynamics can be defined as the concept of reducing drag by making real-time changes to certain devices such that it modifies the airflow around a vehicle. Using such devices also have the added advantages of improving ergonomics and performance along with aesthetics. A significant reduction in fuel consumption can also be seen when using such devices. The objective of this work is to reduce drag acting on a passenger car using the concept of active aerodynamics with grill shutters and air dams. First, analysis has been carried out on a baseline passenger car and further simulated using active grill shutters and air dams for vehicle speed ranging from 60 kmph to 120 kmph, with each active device open from 0° to 90°. The optimized model is then validated for a scaled down prototype in a wind tunnel at 80kmph. Vehicle has been modelled using SolidWorks tool and the simulation has been carried out using ANSYS Fluent. The result shows a significant drag reduction of 12.23% using active grill shutters and air dams.
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Design Analysis of a Retrofit System for an Electric Two Wheeler

Manav Rachna International Institute of Research & Studies-Devendra Vashist
  • Technical Paper
  • 2019-28-2482
Published 2019-11-21 by SAE International in United States
Two wheelers are the major mode of single transport in the metros of India. They contribute about 70% of the auto market unit wise. Also it is proved from the research that for per unit energy consumption they contribute more to the environment emission. Conventional IC engine based energy supply unit can be replaced with an electric DC motor with chargeable battery as the energy source for the two wheelers present in the market. In the current research, engine is replaced with the motor, batteries and controller. The above system is placed on the space emptied by the conventional engine. The design developed is tested on different gradients for identifying the motor torque for minimum and maximum resistances available on the road. The paper provides an insight on the torque requirements based on variable resistances required for two wheelers. Also the system will be used as a retrofit for the existing IC engine bikes to be converted in electric bikes. The paper will help in deign calculation and selection of motor for new designs developed…
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Simulation of Softening and Rupture in Multilayered Fuel Tank Material

General Motors Technical Center India-Vijaya Kumar R L, Biswajit Tripathy, Jayaraj Radhakrishnan
  • Technical Paper
  • 2019-28-2557
Published 2019-11-21 by SAE International in United States
Multi-layered, high-density polyethylene (HDPE) fuel tanks are increasingly being used in automobiles due to advantages such as shape flexibility, low weight and corrosion resistance. Though, HDPE fuel tanks are perceived to be safer as compared to metallic tanks, the material properties are influenced by service temperature. At higher temperatures (more than 80oC), plastic fuel tanks can soften, sag and eventually spill out the fuel, while the extreme cold (less than -20°C) can lead to potential cracking problems. Damage may also occur due to accidental drop while handling or due to an impact from a flying shrapnel. This can be catastrophic due to flammability of the fuel. The objective of this work is to characterize and develop a failure model for the plastic fuel tank material to simulate damage and enhance predictive capability of CAE for chassis and safety load cases. Different factors influencing the material properties such as service temperature, rate of deformation, state of stress etc. were considered to develop a characterization and modelling strategy for the HDPE fuel tank material. Samples cut-out from…
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