Shuffle Parking Ventilation CFD Simulation Training

Description

Shuffle Parking Ventilation Project Description

The present problem simulates the air conditioning inside the shuffle car park using ANSYS Fluent software. In this project, a shuffle parking is designed entirely, with three floors, and eight cars are located on its floors. In this type of parking, cars are parked in such a way that they have to act in a jigsaw puzzle to enter and exit; In this way, the space of a car is empty, and the cars can be parked or taken out of the park by moving the puzzle horizontally or vertically.

In this project, it is assumed that the carbon monoxide flow is emitted through the exhaust of the middle car from the second floor to the interior of the parking lot and pollutes its interior. This project aims to design a proper ventilation system to prevent the spread of pollutants and help eliminate these gases inside the parking. Therefore, several vents have been used on the roof of the parking.

Project Description

The species transport model has been used to simulate the process of carbon monoxide emission into the air inside the parking. So the number of gaseous species is equal to two, including air and carbon monoxide (CO). Therefore, the exhaust outlet is defined as the inlet boundary condition; So that the mass fraction of CO is equal to 1. A UDF is also used to define the mass flow rate of the emitted gas; Because depending on the time, the flow rate of carbon monoxide can be zero or have a variable value. For air vents in the ventilation system, a value of zero for the mass fraction of carbon monoxide is used. However, the inlet velocity condition is used to define the boundary condition of these outlet valves, but the velocity value is applied as a negative value.

Because the goal is to block the flow of polluted air inside the parking to be discharged out of the parking through these vents at a certain speed. To compare the performance of ventilation valves, the amount of suction power or the same amount of negatively defined velocity at these different output limits is considered; So that the speed value of the end valves of the parking has a value equal to -2. 5 m.s-1 and the value of the initial valves (above the car exhaust) has a value equal to -10 m.s-1.

Shuffle Parking Geometry & Mesh

The present model is designed in three dimensions using Design Modeler software. The current model is related to a multi-story parking of the shuffle parking type with a simple building, inside which eight cars are designed. A boundary on the exhaust port of the middle vehicle is defined as the source of carbon monoxide emission, and several boundaries are defined as panels or vents for the exit of polluted air on the roof of the parking lot.

We carry out the model’s meshing using ANSYS Meshing software. The mesh type is unstructured. The element number is 1467439. The following figure shows the mesh.

CFD Simulation

We consider several assumptions to simulate the present model:

• We perform a pressure-based solver.
• The simulation is unsteady.
• The gravity effect on the fluid is ignored.

The following table represents a summary of the defining steps of the problem and its solution:

Results

At the end of the simulation process, the pathline of the carbon monoxide exhaust from the exhaust port of the vehicle is displayed. In the mentioned ventilation system, several air intake vents have been used on the roof of the parking lot to eliminate environmental pollution. There are four panels for air exit at the end side and two panels for air exit at the front side of the parking. Also, the fresh air entering this ventilation system is supplied from the filter plate on the parking wall behind the cars on the middle floor and the front panel of the cars on the lower floor. Although the suction power of the end panels of the roof (-2.5 ms-1) is less than the suction power of the front panels (-10 ms-1), the gas flow after scattering inside the parking from the same end panels Suction to the outside environment.

Analysis

This is because the air pressure entering the parking lot in the rear wall of the cars on the middle floor prevents the direct exit of carbon monoxide gas from the exhaust to the exhaust valve located on top of it. Next, two-dimensional and three-dimensional contours related to velocity, mass fraction of carbon monoxide, mass fraction of air, and gradient mass fraction of carbon monoxide are obtained. Also, using the iso-surface command, a layer of CO gas with a mass fraction of 0.001 is formed to show how the gas is released into the environment in the form of a graphic effect. In general, these contours show well that the carbon monoxide gas emitted from the exhaust port of the vehicle quickly disappears into the interior of the parking. Therefore, the desired ventilation system works well and prevents the significant spread of gas inside the parking.

We obtain all results, including flow path lines and contours, at 5400 seconds.