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Automotive ventilation system - comparison of an influence of boundary conditions on flow from various types of ventilation outlets
Brdečko, Radim ; Pokorný, Jan (referee) ; Lízal, František (advisor)
Diploma thesis deals with a research of the flow in front of three different automotive vents. The velocity field and intensity of the turbulence was measured in detail, using thermoanemometry. After that the same data was measured with PIV method and validation was performed. The difference between achieved data was investigated. The design among the vents was also investigated, because it’s fundamentally affects the air flow. The purpose of this thesis is to obtain data about the velocity field using two methods and their subsequent use to validate numerical simulations, which will be performed in the future. The diploma thesis also contains the calculation of measurement uncertainty.
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Influence of boundary walls on the flow from the ventilation outlet
Molčan, Filip ; Jícha, Miroslav (referee) ; Jedelský, Jan (advisor)
The goal of this work is to experimentally assess the influence of limiting walls of Škoda Octavia 3 automobile cabin to the air jet flowing from the right-front situated automotive vent which is part of a car dashboard. The experiment is performed by the smoke visualization method. There is a single construction option measured for an experiment. The setup of the vanes direction and the air flow rate are modified for this option. The experiment is divided into two phases. In the first phase, the visualization of the free air flow is conducted. In the second phase, exit plates are constructed and consequently, the visualization of the wall-jet flow is conducted. The results of both are compared to each other. The results imply that the influence of the surrounding surfaces must be taken into account with the increasing flow rate for the vanes set in the direction of upper-right, middle-right, and middle-middle. There is a direct interaction between the flow and exit plates (the flow impact, the Coanda effect). The free flow does not contain the information about the mutual interaction between the flow and the exit plates, as it is in the case of the wall-jet flow. In the case of the wall-jet flow, the opening of the flow takes place due to the effect of the impact and the subsequential suction caused by the Coanda effect. The exit plates substituting the car dashboard and the front window contribute to the prevention of the air intake from surrounding space and consequently to earlier flow opening from the vent. The present work also contains the measurement methodology and the image evaluation, the comparison with previous free flow measurements (70% match) and the comparison to the measurement of hot-wire anemometry method.
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Evaluation of functionality of several modifications of ventilation outlet for passenger car cabin
Caletka, Petr ; Hejčík, Jiří (referee) ; Jedelský, Jan (advisor)
This master thesis deals with determination of boundaries of the flow from a benchmark automotive vent (right-front situated – in front of a front passenger) using the smoke visualization. In this thesis is tested a pack of eight different constructional variants which differ among them by the type of deflection grille. The angles of the flow borders are compared to specific directional requirements (defined by ŠKODA AUTO a.s.) and there is evaluated a directability of each of the constructional variant on the bases of these results. The results of experiments show that better directability in vertical plane achieve deflection grilles with horizontal vanes situated closer to orifice of the vent or deflection grilles with higher number of horizontal vanes and lower number of vertical vanes (independently of their location). Directability of the deflection grilles in horizontal plane is analogically better with vertical vanes situated closer to orifice of the vent or with deflection grilles with higher number of vertical vanes and lower number of horizontal vanes (independently of their location).
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Research of Systems for Providing the Quality of the Environment in the Car Cabin
Šíp, Jan ; Kavička, František (referee) ; Volavý, Jaroslav (referee) ; Lízal, František (advisor)
Optimal conditions of indoor environmental quality, especially thermal comfort and indoor air quality, are important because they lead to the active safety of passengers. Long-term exposure to inconvenient temperatures may cause thermal stress and negatively affects the driver’s cognitive functions. These include important abilities of drivers, such as concentration, vigilance, speed of decision-making and others. The inappropriate temperature in the cabin is one of the most dangerous factors causing car crashes. Air indoor quality is negatively affected by exhaust gases or particles from tire wear, which enter the car cabin during ventilation. This can be prevented by using an air recirculation system which does not supply outside air, but it is a closed circuit. This mode, however, causes high CO2 concentration in the cabin which can lead to excessive fatigue. This thesis deals with the influence of different ventilation systems on indoor environmental quality, i. e. thermal comfort and indoor air quality. A partial factor of thermal comfort is the flow field which was investigated downstream of a benchmark automotive vent. CFD was applied to determine the flow field downstream of a vent. The results were validated by experimental data acquired by Constant Temperature Anemometry. CFD has been also used for the evaluation of the thermal comfort of three novel ventilation systems (mixing, ceiling and floor ventilation). The results were validated by experimental data acquired by thermal manikin and climate chamber. Indoor air quality has been evaluated based on the Age of Air. The analytical empirical equation by Rajaratnam can be successfully used also to determine the throw of the jet, which is favorable, especially in light of the fact that both computational methods were not very accurate in velocity decay predictions. The Large Eddy Simulation and Reynolds-averaged Navier–Stokes method are suitable for evaluating the flow field downstream of the automotive vent. The diagrams of comfort zones were evaluated for all regimes based on equivalent temperatures. The best performance in terms of the highest level of human comfort was achieved by the ceiling ventilation in the summer conditions and by the floor ventilation in the winter conditions. From the point of view of the Age of Air, the ceiling air ventilation system is the most suitable for the winter conditions. In the summer conditions the Age of Air values for individual air ventilation concepts are very similar for both interior types.
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Automotive ventilation system - comparison of an influence of boundary conditions on flow from various types of ventilation outlets
Brdečko, Radim ; Pokorný, Jan (referee) ; Lízal, František (advisor)
Diploma thesis deals with a research of the flow in front of three different automotive vents. The velocity field and intensity of the turbulence was measured in detail, using thermoanemometry. After that the same data was measured with PIV method and validation was performed. The difference between achieved data was investigated. The design among the vents was also investigated, because it’s fundamentally affects the air flow. The purpose of this thesis is to obtain data about the velocity field using two methods and their subsequent use to validate numerical simulations, which will be performed in the future. The diploma thesis also contains the calculation of measurement uncertainty.
|
|
|
Influence of boundary walls on the flow from the ventilation outlet
Molčan, Filip ; Jícha, Miroslav (referee) ; Jedelský, Jan (advisor)
The goal of this work is to experimentally assess the influence of limiting walls of Škoda Octavia 3 automobile cabin to the air jet flowing from the right-front situated automotive vent which is part of a car dashboard. The experiment is performed by the smoke visualization method. There is a single construction option measured for an experiment. The setup of the vanes direction and the air flow rate are modified for this option. The experiment is divided into two phases. In the first phase, the visualization of the free air flow is conducted. In the second phase, exit plates are constructed and consequently, the visualization of the wall-jet flow is conducted. The results of both are compared to each other. The results imply that the influence of the surrounding surfaces must be taken into account with the increasing flow rate for the vanes set in the direction of upper-right, middle-right, and middle-middle. There is a direct interaction between the flow and exit plates (the flow impact, the Coanda effect). The free flow does not contain the information about the mutual interaction between the flow and the exit plates, as it is in the case of the wall-jet flow. In the case of the wall-jet flow, the opening of the flow takes place due to the effect of the impact and the subsequential suction caused by the Coanda effect. The exit plates substituting the car dashboard and the front window contribute to the prevention of the air intake from surrounding space and consequently to earlier flow opening from the vent. The present work also contains the measurement methodology and the image evaluation, the comparison with previous free flow measurements (70% match) and the comparison to the measurement of hot-wire anemometry method.
|
|
|
Evaluation of functionality of several modifications of ventilation outlet for passenger car cabin
Caletka, Petr ; Hejčík, Jiří (referee) ; Jedelský, Jan (advisor)
This master thesis deals with determination of boundaries of the flow from a benchmark automotive vent (right-front situated – in front of a front passenger) using the smoke visualization. In this thesis is tested a pack of eight different constructional variants which differ among them by the type of deflection grille. The angles of the flow borders are compared to specific directional requirements (defined by ŠKODA AUTO a.s.) and there is evaluated a directability of each of the constructional variant on the bases of these results. The results of experiments show that better directability in vertical plane achieve deflection grilles with horizontal vanes situated closer to orifice of the vent or deflection grilles with higher number of horizontal vanes and lower number of vertical vanes (independently of their location). Directability of the deflection grilles in horizontal plane is analogically better with vertical vanes situated closer to orifice of the vent or with deflection grilles with higher number of vertical vanes and lower number of horizontal vanes (independently of their location).
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