Experiment Operation During Apollo IVA at 0-g

Experiment: Heat Flow and Convection

Acronym: HFC


Panel face of Apollo 17 Heat Flow and Convection Apparatus.

PI/Engineer: T. C. Bannister/MSFC
Other Contacts: B. R. Facemire/MSFC

Apollo Flight Nos.: 17
Apollo Exp't No.: None

Discipline: Fluid Dynamics (1700) Materials Science - Fluids (2610)

Weight: 3.2 kg
Dimensions: 23 x 23 x 9.6 cm

Manufacturer: Marshall SFC

Description/Purpose:
This was a modified version of the A-14 demonstration and contained three separate experimental tests. Data was obtained with the 16 mm data acquisition camera and from crew observations; both of which were of excellent quality.

The first test was a flow pattern experiment to investigate convection caused by surface tension gradients. The gradients result from heating a thin layer of liquid which generates cellular patterns known as Benard Cells. The apparatus consisted of an open aluminum pan ~7 cm in diameter with electrical heaters attached to the bottom. There was no cover, thus an air/liquid interface existed. The liquid was Krytox® oil with ~0.2% fine Al powder added for visibility, and the solution was released into the pan by a valve and pump arrangement. Baffles around the inside periphery of the pan maintained the liquid level at 2 and 4 mm in depth. The baffles were redesigned after the A-14 mission to assure an even layer of oil across the bottom of the pan. On the A-14 demonstration, the fluid tended to adhere to the walls of the pan. On the A-17 demonstration, the test was conducted twice, once with a 2 mm fluid-depth, and once with a 4 mm depth.

The fluid contained bubbles which were not easily dissipated by stirring. At the 2 mm depth, onset of convection occurred within a few seconds of heat application; whereas, on Earth, the average onset time was ~5 minutes. The fluid was contained by the baffles around the periphery and assumed a convex shape, similar to a perfect lens. The surface was observed to be free of ripples and distortion, and the center thickness was about twice the baffle height of 2 mm.

The Benard cells formed in the 2 mm depth were less orderly and symmetrical than the ground- based patterns and they reached a steady state in ~7 minutes. Cells formed in 4 mm test were more regular and larger than those in the 2 mm test, but the cells did not reach a steady-state condition during the 10 minute heating period.

The radial heating cell was to investigate heat flow and convection in a confined gas a low g conditions. The experiment consisted of a cylinder which contained argon, and was ~6 cm in diameter and 2 cm in length. The initial internal pressure was ~1 atm. Heat was applied by a post heater mounted in the center of the cell. Tempera-ture changes and distribution were monitored by liquid crystal strips which changed color as the temperature changed. Color changes indicated proper operation.

The lineal heating cell unit was to investigate heat flow and convection in a confined liquid at low g. The demonstration consisted of a cylindrical glass container ~3 cm in diameter and 9 cm long, containing Krytox® oil. A disc-shaped heater was located at one end of the cylinder and the temperature changes were monitored by liquid crystal strips. The cell also contained a few magnesium particles to aid visibility. Color changes indicated proper operation.

Unloading from the LM: NA

Transporting by foot or MET: NA

Loading/unloading tools/exp'ts on LRV: NA

Site Selection:
Uncertain, probably in docking tunnel or lower equipment bay of CM.

Deploying experiment:
No comments by crew. The box had two doors which opened..

Check-out of experiment:
No comments by crew.

Operation of experiment:
During the trans-lunar coast. First of two 40 minute demos was begun at 00:33 GMT on 12/9/72. The second was begun 2 hr 20 minutes later. The pan was filled with oil by turning a knob a prescribed number of turns. Because of the presence of bubbles, additional oil had to be transferred by turning the knob more. This may have overfilled the pan and formed a convex surface. As a result, fluid depth was not well known.

Repairs to experiment:
None required, but see operation, above.

Recovery/take-down of experiment:
No comments by crew.

Stowing experiment for return:
No comments by crew.

Loading/unloading samples on LRV: NA

Loading of exp't/samples into the CM:
The pan was filled with oil by turning a knob a prescribed number of turns.

Stowing of package once in the LM: NA

Sampling operations - soil, rocks: NA

Trenching: NA

Raking: NA

Drilling: NA

Navigating/recognizing landmarks: NA

Were there any hazards in the experiment?
i.e. hazardous materials (explosive, radioactive, toxic), sharp objects, high voltages, massive, bulky, tripping hazards, temperatures?
No.

Was lighting a problem?
No

Were the results visible to the crew?
Yes

Would you recommend any design changes?
Some changes were made from the A-14 model to this unit, as described above.

Were any special tools required?
Data Acquisition Camera.

Was the orientation of the experiment (i.e. horizontal/vertical) important? Difficult?
Between the two runs, the experiment was reoriented so that the radial experiment would point perpendicular to the CM spacecraft x axis rather than parallel to it. This should not have made much of a difference, in any case.

Was the experiment successful?
Yes

Were there related experiments on other flights?
Apollo 14 Heat Flow & Convection Experiment, See also Skylab, Shuttle, and Spacelab databases.

Where was it stored during flight?
CM stowage, uncertain.

Were there any problems photographing the experiment?
No.

What pre-launch and cruise req'ts were there?
No comments by crew.

What was different between training and actual operation?
There were bubbles in the test fluid reservoir which caused problems with the experiment.

What problems were due to the suit rather than the experiment?
NA

Any experiences inside the LM of interest from the experiment/operations viewpoint?
Performed on trans-lunar coast by Ron Evans. The mass of the A-17 craft, more fully fueled and with the LM attached, was higher than the mass of the A-14 craft during the operation of the experiment on that mission (during trans-Earth coast without the LM.) The g-jitter might thus have been lower.

References:

The Apollo Spacecraft - A Chronology, NASA SP-4009, Vol. 4., p. 358.

Apollo 17 Heat Flow and Convection Experiments-Final Data Analyses Results, NASA TM X- 64772

Heat Flow and Convection Experiments aboard Apollo 17, Science, vol. 187, 1975, pp. 165-167

Apollo Program Summary Report, section 3.6 Inflight Demonstrations, JCS-09423, April, 1975.

Apollo 17 Technical Crew Debriefing, 4 January 1973, in JSC History Office.