The High-Enthalpy Arc-Heated Facilities at
Arnold Engineering Development Complex
The Arnold Engineering Development Complex (AEDC), Arnold Engineering Development Center before July 2012, is an Air Force Materiel Command facility under the control of the Air Force Test Center (AFTC). Headquartered at Arnold Air Force Base, ...
provide
aerothermal ground test simulations of
hypersonic flight
Hypersonic flight is flight through the atmosphere below altitudes of about 90 km at speeds greater than Mach 5, a speed where dissociation of air begins to become significant and high heat loads exist. Speeds of Mach 25+ have been achieve ...
over a wide range of velocities and pressure altitudes in support of materials and structures development. The facility is composed of three
Arc Heaters: HEAT-H1, HEAT-H2, and Heat-H3 which can heat air up to 13,000
degrees Rankine
The Rankine scale () is an absolute scale of thermodynamic temperature named after the University of Glasgow engineer and physicist Macquorn Rankine, who proposed it in 1859.
History
Similar to the Kelvin scale, which was first proposed in 1848 ...
through a controlled high voltage
direct current
Direct current (DC) is one-directional flow of electric charge. An electrochemical cell is a prime example of DC power. Direct current may flow through a conductor such as a wire, but can also flow through semiconductors, insulators, or even ...
electric arc
An electric arc, or arc discharge, is an electrical breakdown of a gas that produces a prolonged electrical discharge. The electric current, current through a normally Electrical conductance, nonconductive medium such as air produces a plasma (p ...
discharge.
The test unit is owned by the
United States Air Force
The United States Air Force (USAF) is the air service branch of the United States Armed Forces, and is one of the eight uniformed services of the United States. Originally created on 1 August 1907, as a part of the United States Army Signal ...
and operated by
National Aerospace Solutions.
HEAT-H1
The HEAT-H1 Test Unit is an advanced performance arc-heated facility providing high-pressure, high-
enthalpy
Enthalpy , a property of a thermodynamic system, is the sum of the system's internal energy and the product of its pressure and volume. It is a state function used in many measurements in chemical, biological, and physical systems at a constant ...
test conditions for qualification of thermal protection materials, nosetips, and electromagnetic apertures and structures for hypersonic missiles, space access systems, and re-entry vehicles. The test unit utilizes a segmented arc heater with 200 electrically isolated segments which form the heater plenum. The unique segmented construction, with the
anode
An anode is an electrode of a polarized electrical device through which conventional current enters the device. This contrasts with a cathode, an electrode of the device through which conventional current leaves the device. A common mnemonic is ...
and
cathode
A cathode is the electrode from which a conventional current leaves a polarized electrical device. This definition can be recalled by using the mnemonic ''CCD'' for ''Cathode Current Departs''. A conventional current describes the direction in whi ...
at opposite ends of the plenum, allows the arc to be held at a fixed length to optimize heater efficiency, total enthalpy at high pressure, and flow uniformity. Normal operating conditions for the heater are about 20,000
volt
The volt (symbol: V) is the unit of electric potential, electric potential difference (voltage), and electromotive force in the International System of Units (SI). It is named after the Italian physicist Alessandro Volta (1745–1827).
Defi ...
s and 1,200
amps, providing heater chamber pressures up to 120
ATM at high stagnation enthalpies.
The H1 test cell is equipped with a multiple-strut, programmable rotary model injection system capable of positioning one to seven test models sequentially into the test free jet for preset dwell times. Transient calibration probes of various configurations are available to define heat flux and pressure conditions inside the test jet.
HEAT-H2
The HEAT-H2 Test Unit is an arc-heated aerothermal tunnel providing high-enthalpy flow at high
Mach number
Mach number (M or Ma) (; ) is a dimensionless quantity in fluid dynamics representing the ratio of flow velocity past a boundary to the local speed of sound.
It is named after the Moravian physicist and philosopher Ernst Mach.
: \mathrm = \frac ...
s and dynamic pressures simulating hypersonic flight at pressure altitudes up to 120 atm. H2 utilitzes an N-4 Huels-type arc heater to generate high-temperature, high-pressure air for expansion through a hypersonic nozzle into the evacuated test cell.
The combination of the arc heater driver, various nozzle/throat combinations, the evacuated test cell, and exhauster makes possible high-enthalpy flows at Mach numbers from 5 to 9. Direction and distribution of the injected air can be selected to optimize the enthalpy distribution across the flow to match specific test requirements. Run times of 20 minutes or longer are available in HEAT-H2 for selected operating conditions.
HEAT-H3
The HEAT-H3 Test Unit was developed to provide a large, high-pressure arc facility with sufficient size and performance for testing of full- and large-scale missile and re-entry samples and structures. H3 is a 12-module, 50-percent geometric scale-up of H1. The test unit is designated to operate at over twice the available power level and mass flow of H1, with operational pressure up to 150 atm.
See also
*
Arnold Air Force Base
Arnold Air Force Base (Arnold AFB) is a United States Air Force base located in Coffee and Franklin counties, Tennessee, adjacent to the city of Tullahoma. It is named for General Henry "Hap" Arnold, the father of the U.S. Air Force.
There ...
References
External links
Arnold Engineering Development Center(official)
Electric Arc Heater
{{DEFAULTSORT:High-Enthalpy Arc Heated Facility
Electric arcs