tab “Volumes”

This tab is mandatory.

Volumes are the base parameters for a model decompression. They act as a tank of air. This air has a given pressure and temperatures at initial conditions, when t=0 sec.

As soon as one of the volume is connected to the ambient, the air located in the different volumes will be sucked by the ambient, leading to pressure on partitions.

Parameters

Volumes parameters

	description	default	units
id	Volume ID	mandatory	no units
label	Volume label	mandatory	no units
deck	Deck Location	mandatory	no units
group	Group (sub-deck) identification for Unified Model	blank	no units
sta	Station	mandatory	[m | in]
rbl	RBL	mandatory	[m | in]
volume	Volume (size value)	mandatory	[m^3 | in^3]
deor	Deck Explosion Occupation Rate	0.0	no units
veor	Volume Explosion Occupation Rate	0.0	no units

Volumes/id

Flags

Type: Int in range [0; +∞] | Default: None | Mandatory: True | Unique: True

Short description:

Volume ID [no units]

Volumes/label

Flags

Type: Str | Default: None | Mandatory: True | Unique: False

Short description:

Volume label [no units]

Volumes/deck

Flags

Type: Int in range [-1; 2] | Default: 0 | Mandatory: True | Unique: False

Short description:

Deck Location [no units]

The mandatory deck parameter is used for organizing the results only and has no effects on calculations themselves. An integer is to be provided as per deck location, knowing by default:

• deck==-1: volume located in the cargo
• deck==0: volume located at the main deck
• deck==1: volume is on the second deck (in case of dual deck body)
• deck==2: volume is a ceiling compartment

Volumes/group

Flags

Type: Int in range [-∞; +∞] | Default: nan | Mandatory: False | Unique: False

Short description:

Group (sub-deck) identification for Unified Model [no units]

Volumes/sta

Flags

Type: Float in range [-∞; +∞] | Default: 0 | Mandatory: True | Unique: False

Short description:

Station [m] or [in]

Volumes/rbl

Flags

Type: Float in range [-∞; +∞] | Default: 0 | Mandatory: True | Unique: False

Short description:

RBL [m] or [in]

Volumes/volume

Flags

Type: Float in range ]0; +∞] | Default: None | Mandatory: True | Unique: False

Short description:

Volume (size value) [m^3] or [in^3]

Volumes/deor

Flags

Type: Float in range ]-1; 1[ | Default: 0.0 | Mandatory: False | Unique: False

Short description:

Deck Explosion Occupation Rate [no units]

DEOR stands for “Deck Explosion Occupation Rate” and defines how the volume is reduced when the explosion occurs somewhere in the same deck as the given volume. For example, this parameter is useful to initialize the cargo volumes with container inside when explosion occurs in the cargo.

Volumes/veor

Flags

Type: Float in range ]-1; 1[ | Default: 0.0 | Mandatory: False | Unique: False

Short description:

Volume Explosion Occupation Rate [no units]

VEOR stands for “Volume Explosion Occupation Rate” and defines how the volume is reduced when the explosion occurs in the volume itself.

DEOR/VEOR decision tree

It is important to understand how ESonix interprets DEOR and VEOR. Before each load-case triggering, all the volumes are checked against the explosion’s volume. For a given load-case, each volume can be in one of the following situation:

1. Case 1: the explosion volume
2. Case 2: located at the same group (or deck if group parameter is blank)
3. Case 3: anywhere else

Depending on the situation, ESonix will alter the volume’s volume as described in the DEOR/VEOR decision tree.

For each Load Case LCID:

For each Volume VID located in group GID:

DEOR - VEOR decision tree

By default (when left blank), both parameters are set to 0, such as both alteration equations (\(V_{LCID}=f(\texttt{DEOR})\) and \(V_{LCID}=f(\texttt{VEOR})\)) are invariants.

The alteration equations are:

1. Case 1: Explosion in the volume: \(V_{LCID}=V_{model} - \texttt{VEOR} \times V_{model}\).
2. Case 2: Explosion in the group (or deck): \(V_{LCID}=V_{model} - \texttt{DEOR} \times V_{model}\).
3. Case 3: Explosion in another group (or deck): no alteration

See also

Tutorial #4 uses “VEOR” parameter in the section Unified model.

Preprocessing

Right before the actual run is solved, the model the user uploaded is preprocessed. For the volumes, it consists in setting blank cells to default values as defined in Volumes parameters.

Common examples

Volume reduction for a cargo compartment using DEOR

Volumes are really easy to idealize. Nevertheless, we will illustrate the use of the DEOR parameter.

A regular LD-6 cargo container has an internal volume of 8.9m³. Let say that a cargo compartment has a volume of 25m³ and can therefore welcome two containers, as shown in ld6_loaded_cargo.

It may be interesting to simulate the A/C with cargo empty for an explosion occurring in the cabin, and cargo occupied for an explosion in the cargo. Instead of creating two models, run two analysis and compare them, it is more convenient to inform ESonix of the expected behavior.

Setting DEOR will inform ESonix that, when the explosion occurs in the cargo, then the volumes of the cargo should be reduced by the DEOR factor.

If DEOR is null or blank, no reduction will therefore be applied.

In the current example, the volume occupied by the two containers is \(8.9 \times 2 = 17.8m^3\). Assuming that the both containers are full, the volume of air available is therefore \(25-17.8=7.2m^3\). The initial volume of air is therefore reduced by the DEOR coefficient \(DEOR=1 - \frac{7.2}{25}=0.712\).

Cargo compartment with two LD6 containers

Cargo Volume example featuring DEOR

Column	User input	Preprocess	Actual input
id	9		9
volume	25		25
label	“cargo example”		“cargo example”
deck	-1		-1
sta	5		5
rbl	0		0
deor	0.712		0.712
veor		Default to zero	0