Vellore Institute of Technology (VIT) is a private university located in&nbsp;Tamil Nadu, India. Founded in 1984, as Vellore Engineering College, the institution offers 20 undergraduate, 34 postgraduate, four integrated and four research programs. It has campuses in Vellore, Amravati, Bhopal and Chennai.

VIT is one of the top ranked private universities in India according to NIRF, THE and QS Rankings.&nbsp;Govt. of India has recognized&nbsp;VIT, Vellore as an&nbsp;Institution of Eminence. This has allowed VIT to take independent quality initiatives and move up in world ranking.

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VIT University

In the automotive applications, the main functionality of the HVAC system includes heating, ventilation, and cooling or air-conditioning of the vehicle to achieve the desired indoor thermal comfort. In the current scenario, the conventional vapor compression based HVAC system is widely used. The typical refrigerants used to operate this equipment include HFCs and HFOs which are susceptible to cause an environmental hazard. This article aims to assess the performance of a hypothetical solar-driven thermoelectric based rotary desiccant wheel HVAC system (D-HVAC) to be used for automotive applications. The D-HVAC system uses the desiccant wheel to remove the latent heat, energy wheel to remove the sensible heat, evaporating coolers to achieve further cooling, the regeneration of the desiccant wheel by hot air and water as the refrigerant. In the case of a solar-driven-DHVAC system, solar energy is utilized for the regeneration of the desiccant wheel in place of hot air. However, the intensity of incident solar energy varies throughout the day. To compensate for this energy fluctuation an additional thermoelectric system (Peltier device) can be added to achieve the optimum regeneration of the desiccant wheel. The Peltier device avails the advantage to simultaneously heat the regeneration air and cool the process air to achieve the highest cooling coefficient of performance (COP) of the solar-driven D-HVAC system. The usage of PV cells to produce the required electricity to operate the blowers (for process air and regeneration air) and motor of the rotary desiccant wheel and TEC. Overall, through numerical simulation, the increment in the COP of the solar-driven thermoelectric based rotary desiccant wheel HVAC system in comparison with the simple D-HVAC system and conventional vapor compression based HVAC system are investigated. © 2020 SAE International. All rights reserved.

World University root node

Department of Thermal and Energy Engineering

School of Mechanical Engineering

Vellore Campus

SAE Technical Papers

Simulation of the performance of solar driven thermoelectric based rotary desiccant wheel HVAC system

The conventional vapor compression refrigeration cycle based air dryers are used widely for the applications of required pressure dew point temperature up to +2~3°C. However, for the industrial and pneumatic applications, the required pressure dew points are as low as -10°C, -30°C or -50°C and also up to -75°C, which is achieved by the adsorption based packed bed desiccant dryers. This paper presents the results of numerical simulation of hybrid packed desiccant beds under coupled heat and mass transfer during the adsorption and desorption phases under wide operating conditions. The bed containing a homogenous mixture of multiple desiccant types along the vertical axial direction has been investigated. A CFD code has been developed using the finite volume method which models the heat conduction and mass diffusion for these hybrid beds. The numerical results of the present model are validated with experimental data from literature and show good agreement for exit air temperature and moisture content. The improvement in moisture removal capacity, relative moisture removal efficiency, and dew point temperature or pressure dew point for these hybrid desiccant beds are investigated. © 2020 SAE International. All rights reserved.

Simulation of hybrid packed desiccant beds for dehumidification and drying

In order to meet the stringent emission norms like EU6 and EU7 together with CAFÉ/CAFC norms, down-sizing of the engine is one of the thrust areas of focus among the OEMs. To this end, keeping the engine size small but to achieve the required power output, advanced Turbo charged Gasoline Direct Injection engine technology (TGDI) has emerged. However, TGDI technology is susceptible to an abnormal combustion phenomenon termed as Low Speed Pre-Ignition (LSPI) event. This event happens prior to the intended combustion, which causes the catastrophic engine damage. Several studies in terms of simulation and experiments to understand this phenomenon are reported in the literature. The main factors influencing this occurrence are found to be engine design and calibration, fuel types and engine oil formulation (in terms of calcium content). In this paper, advanced methods to handle the LSPI occurrence severity and component level advances in design robustness to avoid the engine damage are reported. The developed techniques include robust piston design, Piston ring design and coating technologies. In overall, the techniques related to engine design to predict the LSPI occurrence in terms of peak cylinder pressure (PCP) and number of events are summarized. © 2020 SAE International. All rights reserved.

Advanced methods to handle LSPI in TGDI engines

This work, Seamless Austenitic 213 tube is welded with Seamless Austenitic 387 tube plate through friction welding of tube to tube plate using an external tool (FWTPET) method in presence of backing block by using clearance fit method. Further, the analysis of microstructural features on the interface of weld exhibit that the FWTPET is able to generate flawless welds. In all nine various work specimen which welded under the various circumstances, the hardness value, tensile strength have taken. In this work, two type of specimen has taken where one kind is the tube which contains no hole and another one is with the hole in the circumference. 806.28 MPa and 746.5 MPa were the optimum strength for the workpiece which is not a having a hole and having the hole on the circumference.

Department of Manufacturing Engineering

Materials Science Forum

Metal Joining Technique of SA 213 Tube and SA 387 Tube Plate Grade Materials Using Backing Block by Clearance Fit Condition

Fogging (i.e. condensation of water vapor) in headlamps in severe weather conditions present both a performance and potential safety concern for automotive companies. Conventional headlamps are based on incandescent bulbs. In recent times, LED lighting has increasingly become the norm. However, LED based headlamps are prone to higher levels of fogging because they inherently produce less heat than the conventional incandescent or halogen bulbs. A headlamp design must be able to dispose all the formed condensate/fog in a fixed time even under severe thermal conditions. It is of great importance for the car manufacturer to be able to simulate the risk of condensation early in the design stage with an eye on the overall cost reduction. The combined use of experimental studies and numerical modelling is important to optimize headlamp design and to produce high-performance headlamps. Most of the available literature on headlamp defogging simulation is based, primarily, on 2D geometries with simplified physics. However, in reality, the flow and thermal field inside of a headlamp assembly is highly complicated, encompassing conduction, convection, radiation, phase change and varying ambient conditions. This paper presents an overview of experimental and numerical investigations of the defogging process in an automotive headlamp. In this study, the Eulerian Wall Film (EWF) approach is implemented on a three-dimensional geometry to capture the underlying physics governing the defogging phenomenon inside the headlamp. Lab test observations indicate that the numerical predictions closely agree with the experimental data. Moreover, this study includes simulations on headlamp defogging characterization for different kinds of lens materials. Lenses made of glass and polycarbonate are considered in the analysis to quantify the impact of these materials on defogging performance, thus, enabling the selection of an appropriate lens material in terms of cost and performance with reduced developmental cycle time. The validated numerical prediction method can be used to study the risk of condensation and the required defogging early in the design stage. Copyright © 2016 SAE International.

Automotive LED Headlamp Defogging: Experimental and Numerical Investigation

This article discusses a detailed Computational Fluid Dynamics study to assess the efficiency of the conformal heat and cool system associated with an injection molding process. The study involves characterizing the fluid flow and heat transfer behavior in an injection mold designed with conformal heat and cool circuits. The key result of interest is uniform temperature distribution over the cavity profile. Further, the study involves identifying the important geometrical as well as flow parameters that have the significant influence on optimizing the heat up and cool down time, which promotes uniform temperature distribution on the cavity profile. The formation of uniform temperature distribution leads to the better quality and aesthetics of the injection molded parts. Importantly, molding defects such as knit lines, flow marks, etc., are reduced to a greater extent compared to conventional injection molding processes. Copyright © (2014) by the Society of Plastics Engineers All rights reserved.

Annual Technical Conference - ANTEC, Conference Proceedings

Computational fluid dynamics study of conformal heat and cool technology applied in injection molding

This article describes a simple and elegant compact higher order finite-difference based numerical solution technique to the primitive variable formulation of unsteady incompressible Navier Stokes equations (UINSE) on staggered grids. The method exploits the advantages of the D'yakanov ADI-like scheme and a non-iterative pressure correction based fractional step method. Spatial derivatives are discretized to fourth order accuracy and the time integration is realized through the Euler explicit method. The fast and efficient iterative solution to the discretized momentum and pressure Poisson equations is achieved using a variant of conjugate gradient method. Spatial accuracy and robustness of the solver are tested through its application to relevant benchmark problems.