Slotted Cylinder Grain Geometry Appendix; Tab Inputs

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This page discusses the input details of the "Slotted" Grain geometry in the Rocket Motor Simulation Module.

The Slotted Cylinder grain geometry input tab is shown in the following figure.

The following categories of inputs are shown:

Propellant Parameters in the upper left hand corner.
Grain Gross Parameters in the lower left hand corner.
Grain Feature Parameters in the lower right hand corner.

Also shown in the upper left hand corner is a visualization of the grain cross section as defined by the Grain Feature Parameter inputs, along with an Update Display button used to refresh the display of the grain cross section, if required.

The Propellant Parameters inputs are:

Rocket Grain Type: A pull down menu enabling the user to select the desired geometry. For this grain geometry select "Slotted Cylinder".
Propellant Name: A field displaying the nomenclature of the propellant grain if read in from the reference books. When propellant chemistry is loaded from reference books, that descriptor will be displayed.
Number of Surfaces Burning: A numeric option of 0,1, or 2 to indicate the number of grain end surfaces involved in combustion. Since both ends of this grain are prevented from burning (inhibited), enter a 0.

Under the Grain Gross Parameters input category:

The Number of Grains is the number of energetic grains contained inthe rocket motor.
The Grain Length is the length of the energetic material that comprises the rocket motor grain.
The Grain External Diameter is the Outside Diameter, the exterior diameter of the rocket motor grain. This diameter should have been passed through from the Rocket Motor Sizing Utility .
The Grain Interior Diameter is the Interior Diameter, the interior diameter of the rocket motor grain, shown on the previous page.
The Neck Down Volume is the volume of any necked down section of the rocket motor grain.
The Neck Down Diameter is the diameter of any necked down section of the rocket motor grain.

Under the Grain Feature Parameters input category:

Number of Slots, is the number of aft end slot features for the grain being analyzed. This is an integer value. Generally, if the burning surface area requirements can be met with an odd number of features, this is preferred as an odd number prevents combustion instabilies arising from acoustic sources.
The Slot Depth is the AL1 dimension, the length of the slot as measured from the aft end of the grain.
The Grain End Dome Radius is the R0 Dimension in the picture of the rocket motor grain, shown on the previous page.
The Slot Width is the X0 Dimension in the picture of the rocket motor grain, shown on the previous page.