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Technical Paper

Evaluation of Cabin Comfort in Air Conditioned Buses Using CFD

2014-04-01
2014-01-0699
The objective of the work presented in this paper is to provide an overall CFD evaluation and optimization study of cabin climate control of air-conditioned (AC) city buses. Providing passengers with a comfortable experience is one of the focal point of any bus manufacturer. However, detailed evaluation through testing alone is difficult and not possible during vehicle development. With increasing travel needs and continuous focus on improving passenger experience, CFD supplemented by testing plays an important role in assessing the cabin comfort. The focus of the study is to evaluate the effect of size, shape and number of free-flow and overhead vents on flow distribution inside the cabin. Numerical simulations were carried out using a commercially available CFD code, Fluent®. Realizable k - ε RANS turbulence model was used to model turbulence. Airflow results from numerical simulation were compared with the testing results to evaluate the reliability.
Technical Paper

FE Prediction of Thermal Performance and Stresses in a Disc Brake System

2006-10-31
2006-01-3558
The brake system is one of the most critical systems in the automotive vehicle. Its design is a challenging task since stringent performance and packaging requirements are to be fully met - optimizing the brake performance and weight of the brake system. The brake disc is an important component in the braking system which is expected to withstand and dissipate the heat generated during the braking event. Validation of brake disc design through CAE/FEA is presented in this paper. The procedure for prediction of thermal performance was developed in-house, tuned and verified by correlating with Test data available for existing-design and then applied to the new-design brake disc. The correlation achieved for the existing-design brake disc (both solid and ventilated), procedure for prediction of thermo-mechanical performance (heat transfer coefficient estimation, temperature distribution etc.) are also included.
Technical Paper

Sensitivity Analysis of Windshield Defrost Characteristics Impact on Occupant Thermal Comfort

2017-03-28
2017-01-0143
During cabin warm-up, effective air distribution by vehicle climate control systems plays a vital role. For adequate visibility to the driver, major portion of the air is required to be delivered through the defrost center ducts to clear the windshield. HVAC unit deliver hot air with help of cabin heater and PTC heater. When hot air interacts with cold windshield it causes thermal losses, and windshield act as sink. This process may causes in delay of cabin warming during consecutive cabin warming process. Thus it becomes essential to predict the effect of different windscreen defrost characteristics. In this paper, sensitivity analysis is carried for different windscreen defrosts characteristics like ambient conditions, modes of operation; change in material properties along with occupant thermal comfort is predicted. An integrated 1D/3D CFD approach is proposed to evaluate these conditions.
Technical Paper

Thermal Performance Prediction of Jet Lubricated Transmission System using Computational Methods

2017-10-08
2017-01-2437
The jet lubrication method is extensively used in the constant mesh high performance transmission system operating at range of speeds though it affects mechanical efficiency through spin power loss. The lubrication jet has a key role to maintain the meshing gears at non-fatal thermal equilibrium by effectively dissipating the heat generated to the surrounding. Heat transfer coefficient (HTC) is the indicator of the thermal behavior of the system, which provides great insight of efficient lubrication system that needs to be employed for prescribed type of transmission. In this study, a segment of the transmission unit which constitutes a gear pair is used for the simulation. Parametric study is carried out by considering the critical parameters affecting the thermal performance such as lubrication jet flow rate and rotational motions of the gears with speeds and temperatures.
Technical Paper

Design of Experiments Enabled CFD Approach for Optimizing Cooling Fan Performance

2014-04-01
2014-01-0658
Increasing demands on engine power to meet increased load carrying capacity and adherence to emission norms have necessitated the need to improve thermal management system of the vehicle. The efficiency of the vehicle cooling system strongly depends on the fan and fan-shroud design and, designing an optimum fan and fan-shroud has been a challenge for the designer. Computational Fluid Dynamics (CFD) techniques are being increasingly used to perform virtual tests to predict and optimize the performance of fan and fan-shroud assembly. However, these CFD based optimization are mostly based on a single performance parameter. In addition, the sequential choice of input parameters in such optimization exercise leads to a large number of CFD simulations that are required to optimize the performance over the complete range of design and operating envelope. As a result, the optimization is carried out over a limited range of design and operating envelope only.
Technical Paper

Cabin and Battery Cooling Performance Trade-off in an Electric Vehicle

2020-08-18
2020-28-0004
Electric vehicles (EVs) carries two main anxieties in users which are its range and battery life, hence these are important parameters to be taken care of during electric vehicle development. Range of EV depends on many parameters such as vehicle weight, heating ventilation and air conditioning (HVAC) system, battery cooling system (BCS), traction cooling system (TCS) and other electrical loads, which consumes power from a High Voltage (HV) battery. Severe hot ambient in India requires a big size HVAC system, on the other hand, the battery pack needs refrigerated cooling system to keep its temperature in control. Hence, the major parasitic consumers in an EV are HVAC and BCS. In order to enhance the overall efficiency, a trade-off between these two systems is crucial, as both the systems are served with common compressor and condenser in dual loop refrigerant circuit.
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