Papers by Keyword: Baffle

Abstract: Cleaner melt transfer is critical to the broader use of recycled aluminium alloys in high-end structural casting applications, where oxide bifilms and intermetallic inclusions, such as Fe-containing intermetallics, can significantly affect the casting's mechanical properties. In counter-gravity low- and high-pressure casting, the launder system must not only promote the sedimentation of inclusions but also deliver a stable, cleaner melt to the crucible. Prior research showed that 15° double baffles in the mid-section of the sedimentation launder at a flow rate of 100 kg·h^-1 provide high efficiency. The present work investigates the influence of baffle design at the launder-crucible interface, where the melt enters the crucible before casting. Fluid dynamic simulations were carried out at a 100 kg·h^-1 flow rate for three inlet configurations: (i) full baffle; (ii) lifted baffle; and (iii) split baffle. Inclusions of various densities and diameters were tracked. Results indicate that the full baffle, while beneficial as a benchmark and efficient, is impractical because it generates fresh oxide surfaces. The lifted baffle provided the most effective reduction in inclusions, like the full baffle setup, enhancing sedimentation and suppressing entrainment, while the split baffle showed intermediate behaviour. Moreover, the lifted configuration promoted centrifugal flow (at lower velocities, it still made a partial contribution) within the crucible, directing inclusions towards the crucible wall and the stagnation-velocity zone, and enabling the crucible itself to act as a final sedimentation stage before the counter-gravity pump extracts the melt. These results demonstrate that combining mid-launder optimisation with crucible inlet baffle design enables cleaner, more automated melt delivery, thereby strengthening the use of recycled aluminium alloys in structural casting applications.

Abstract: The present study deals with the numerically investigation of developing laminar natural convection in the vertical double-passage porous annuli formed by three vertical concentric cylinders of which the middle cylinder is a thin and perfectly conductive known as baffle. In this analysis, two thermal conditions are considered namely, either inner or outer cylindrical wall is constantly heated while the opposite wall is insulated. An implicit finite difference technique is employed to solve the boundary layer equations in both the annular passages. The temperature profiles and velocity profiles in axial as well as radial directions have been presented for different values of Grashof number, Darcy number, baffle position and radius ratio. The results reveal that both physical and geometrical parameters have profound influence on the development of velocity and thermal fields as well as heat transfer rate.

Abstract: The buoyancy-induced air flow through a two-dimensional vertical ventilation channel is calculated. One of the channel walls is heated uniformly, and the other wall is adiabatic. A thin baffle is placed on the heated wall to manipulate the air flow through the channel. Numerical results are obtained for baffles of different lengths and placed at various heights along the heated wall. It is found that the baffle is effective in weakening a reverse flow at the exit of the channel, and significant enhancement of ventilation performance may be achieved with the presence of the baffle.

Abstract: The aim of this article is to highlight the impact of the fuel movements inside the plastic fuel tank (waves) for the client perception of noise. Today there isn’t a clear methodology regarding the reproducing the fuel waves, but there are different approaches to be taken into account and also there is an innovative potential. Due to the fast technological progress the body in white and not only, the entire vehicle became lighter and lighted. A consequence of this great achievement is that the client can hear easier the sound produced by different components of the car. The plastic fuel tank can be considered such a component. The authors have done a deep analysis of present automotive fuel tanks and propose solutions for breaking the waves produced inside fuel tanks, so as to reduce the slosh noise effect. The studies will be continued during the doctoral approach of the first author.

Abstract: Results from numerical investigation of laminar natural convection inside a differentially heated square enclosure with a thin baffle attached to the cold wall are reported. The effect of the baffles on the flow and temperature fields were analyzed for baffle lengths equal to 20, 35 and 50 percent of the width of the enclosure, attached at three locations for Ra = 10⁴, 10⁵, 10⁶ and Pr = 0.707. The presence of a baffle on the cold right wall affects the strength of the clockwise rotating primary vortex. Reduced flow and heat transfer are observed. Longer the baffle more pronounced the effect on the flow field. Secondary convection cells are seen between the baffle and the bottom wall for certain cases. Reduction in average Nusselt Number is observed on the cold wall with the baffle than the hot wall.

Abstract: Baffles are frequently used to reduce flow speed and to change fluid passages by directly blocking oncoming flow. This study employed multi-stacked porous baffle obstructions to enhance the flow relaxations of water-soluble buoyant gases inside an odor removing basin system. We performed qualitative flow visualization by using tracing particles in working fluid to evaluate the effects of porous baffles. Particle image velocimetry technique was also employed to quantitatively analyze the flow field around the baffle regime. As a result, oncoming two-phase bubbly flow from the basin bottom regime was bent, passing the edge of a porous baffle plate. The main stream speed and momentum were effectively reduced by the installed porous flow obstruction devices.

Abstract: Exhaust noise is one of the noise pollution to the environment and it will cause interference that may harm the activity or balance of human. A muffler is designed to minimize transmission caused by exhaust gases. In this paper, the principle of transfer matrix method is used to analyze the transmission loss. The method is used for developed source code programming to predict muffler performance. The result from programming show excellent agreement with the previous established research paper. This programming is applied for baffle effect to determine transmission loss.

Abstract: Recirculation region behind a fume cupboard sash is the potential contributor to the leakage of the contaminants due to its large size. This is found from the computational fluid dynamics (CFD) simulation of SERVCO fume cupboard using κ-ω turbulence model. For a good fume cupboard, the recirculation zone needs to be minimized while maintaining the flow distribution to all area in the fume cupboard. The opening on the baffle may reduce the recirculation zone which in turn may reduce back flow that is the cause of leakage. In this paper, the effect of shape of baffle openings on flow distributions of a SERVCO fume cupboard will be presented as a result of CFD. The results are presented in terms of velocity vectors Vy (in the direction towards the sash opening) at different cross sections for 4 opening shapes. The opening is found to improve the airflow distribution.

Abstract: Influences of arc-shaped baffles turbulators (ASB) on thermal behaviors in a solar air heater channel are studied. In the experiment, the ASB with three pitch ratios (P/e) are placed on the absorber plate (bottom channel wall in this case) to generate stronger turbulence intensity in the channel. The distributions of temperature and local Nusselt number contours in the absorber plate fitted with ASB are observed with thermochromic liquid crystal (TLC) sheet. The results reveal that the heat transfer increases with the decrease in P/e due to longitudinal vortex flow effect. The heat transfer from employing the ASB at P/e = 4.0, 6.0 and 8.0 is higher than the smooth channel around 116%, 120% and 127%, respectively. This indicates that the ASB pitch spacing is optimal at 8 times baffle height in the present work.

Abstract: Transducer with large directivity and high transmitting sensitivity is designed and fabricated. It is a sandwich transducer with composite horn and it has a finite baffle. A novel model considering the dimension of baffle is deduced, the directivity of transducers are calculated under different conditions. The computations of models agree with the experimental data well. The maximum transmitting voltage response level of the sandwich transducer is 143dB (1V/μPa) and the directivity is up to 99°(-3dB) at the resonance frequency of 75.6kHz.