Discussion: “Incipient Boiling Superheat in Liquid Metals” (Chen, J. C., 1968, ASME J. Heat Transfer, 90, pp. 303–312)

Schultheiss, G.F.; Smidt, D.

doi:10.1115/1.3580106

Cited by 2 publications

(1 citation statement)

References 7 publications

(18 reference statements)

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“…A consistent trend has been established in the literature, showing that increased impurity concentration significantly diminishes incipient boiling superheats (Dwyer 1976). Changes in oxygen concentration from 3 to 9 parts per million have been shown to reduce the incipient boiling superheat from 3.5°C to 0.8°C on stainless steel with 0.4-mm-diameter cavity at 1073 K (Schultheiss and Schmidt 1969). The finding of significant oxygen in the distillate contained within the test capsule answered many questions raised from the failure of heat pipes #1-#3.…”

Section: Failure Mode Identificationmentioning

confidence: 98%

Heat-Pipe Development for Advanced Energy Transport Concepts Final Report Covering the Period January 1999 through September 2001

Reid¹,

Sena²,

Martinez³

2002

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This report summarizes work in the Heat-pipe Technology Development for the Advanced Energy Transport Concepts program for the period January 1999 through September 2001. A gas-loaded molybdenum-sodium heat pipe was built to demonstrate the active pressure-control principle applied to a refractory metal heat pipe. Other work during the period included the development of processing procedures for and fabrication and testing of three types of sodium heat pipes using Haynes 230, MA 754, and MA 956 wall materials to assess the compatibility of these materials with sodium. Also during this period, tests were executed to measure the response of a sodium heat pipe to the penetration of water. _______________________ 1.0 Sodium Heat-Pipe Safety Tests The Phase II progress report described tests of water injection into an ambient-temperature sodium-filled heat pipe. Separate tests were performed on heat pipes with different penetration diameters, 0.25 mm and 0.58 mm. In these tests, water was introduced into the heat pipe at 500 kPa absolute pressure. An additional test was conducted with a 4.8-mm-diameter penetration at 77 kPa atmospheric pressure. At no time during any of these tests did the heat-pipe wall temperature rise by more than 50°C. In each test, similar amounts of heat were released-on the order of 10 3 J, ~2% of the total possible heat of reaction from the available sodium inventory. To quantify the effect of penetration size and higher injection pressure on reaction extent, a series of tests was conducted. Two different penetration diameters were selected (0.58 mm and 2.56 mm) between the extremes of the previous tests. Water was injected into the pipe at ~2 MPa. A picture of the apparatus used in these tests is shown in Figure 1. Two heat pipes were made: each is 30 cm long and built of 3/8-inch, Schedule 40, Haynes 230 pipe. Three layers of 100-mesh stainless-steel screen lined the inside of each heat pipe. Each pipe was charged by vacuum distillation with 5.5 g of sodium that, with a saturated wick, left about a gram of free sodium in the vapor space. A complete sodium-water reaction would liberate 112 kJ, sufficient to increase the heat pipe's temperature to 1070 K. The hydrogen pressure generated by a sodium-water reaction that progressed near completion would be more than adequate to breach the wall of the heat pipe.

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Section: Failure Mode Identificationmentioning

confidence: 98%