Crawford burner
Encyclopedia
A Crawford burner is a device used to test burn rate (chemistry)
of solid propellants. It is also known as a strand burner.
A Crawford burner consists of a small pressure vessel in which a thin bar of propellant to be tested is mounted on a stand. The bar is coated with an external coating so that burning cross-sectional surface is restricted. The propellant is ignited at one end and burned to the other end. Wires are embedded in the propellant at certain intervals of distance so that when the propellant burning reaches the wire, it sends off electrical signals. These wires are connected to a chronometer and the electrical signals are recorded at different time intervals so that burning rate can be measured.
The burning rate measured from a strand burner is typically 4 to 12% less than actual burning rate observed in rockets. This is because the high temperature conditions in actual rocket are not simulated. The heat transfer characteristics are also different. Nevertheless, the strand burner experiment is easy to perform, can be repeated and a qualitative picture of the burning rate is obtained. The temperature sensitivity of burning rate is usually calculated from strand-burner test data.
Burn rate (chemistry)
In chemistry, the burn rate is a measure of the linear combustion rate of a compound or substance such as a candle or a solid propellant. Burn rate is measured in length over time, such as "mm/second" or "inches/second". Burn rate is a property of combustible substance and it quantifies the...
of solid propellants. It is also known as a strand burner.
A Crawford burner consists of a small pressure vessel in which a thin bar of propellant to be tested is mounted on a stand. The bar is coated with an external coating so that burning cross-sectional surface is restricted. The propellant is ignited at one end and burned to the other end. Wires are embedded in the propellant at certain intervals of distance so that when the propellant burning reaches the wire, it sends off electrical signals. These wires are connected to a chronometer and the electrical signals are recorded at different time intervals so that burning rate can be measured.
The burning rate measured from a strand burner is typically 4 to 12% less than actual burning rate observed in rockets. This is because the high temperature conditions in actual rocket are not simulated. The heat transfer characteristics are also different. Nevertheless, the strand burner experiment is easy to perform, can be repeated and a qualitative picture of the burning rate is obtained. The temperature sensitivity of burning rate is usually calculated from strand-burner test data.
External links
- http://members.aol.com/nonillion/staburn.html
- Crawford Burner System (Strand Burner)