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:

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

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