Some Parameter Boundaries Governing Microgravity Pool Boiling Modes
TL;DR: Pool boiling experiments were conducted in microgravity on five space shuttle flights, using a flat plate heater consisting of a semitransparent thin gold film deposited on a quartz substrate that also acted as a resistance thermometer.
read more
Abstract: Pool boiling experiments were conducted in microgravity on five space shuttle flights, using a flat plate heater consisting of a semitransparent thin gold film deposited on a quartz substrate that also acted as a resistance thermometer. The test fluid was R-113, and the vapor bubble behavior at the heater surface was photographed from beneath as well as from the side. Each flight consisted of a matrix of three levels of imposed heat flux and three levels of initial bulk liquid subcooling. In many of the total of 45 experiments, steady nucleate boiling was observed from 16-mm movie films, where a large vapor bubble formed and remained slightly removed from the heater surface, with small vapor bubbles growing on the heater surface, and on contact coalescing with the large bubble. Computations of the forces associated with the momentum transfer in this process, which counters the Marangoni convection effects tending to impel the large bubble toward the heater surface, have been completed for all cases where applicable. The modes of pool boiling observed with successive increases in levels of heat flux in microgravity are categorized as: (i) minimum or incipient nucleate boiling; (ii) nucleate boiling with vigorous motion of the bubbles adjacent and parallel to the heater surface, impelled by Marangoni convection effects; (iii) nucleate boiling followed by coalescence with a neighboring large vapor bubble; (iv) partial dryout of the heater surface, in parallel with nucleate boiling; (v) complete dryout. The boundaries between these modes are delineated graphically as a function of the imposed heat flux and initial bulk liquid subcooling, together with the levels of the forces holding the large bubbles, acting as vapor reservoirs, away from the heater surface for the steady nucleate boiling mode.
read more
Chat with Paper
AI Agents for this Paper
Find similar papers on Google Scholar, PubMed and Arxiv
Write a critical review of this paper
Analyze citations of this paper to find unaddressed research gaps
Citations
Review of flow boiling and critical heat flux in microgravity
TL;DR: In this paper, a review of the literature concerning two-phase flow and heat transfer in reduced gravity is presented, where different methods and platforms dedicated to exploring the influence of reduced gravity, including ground flow boiling experiments performed at different orientations relative to Earth gravity.
155
A modified bubble dynamics model for predicting bubble departure diameter on micro-pin-finned surfaces under microgravity
TL;DR: In this paper, a modified bubble dynamics model based on force balance is proposed to predict bubble departure diameter well on the micro-pin-finned surface, which considers the role of drag force of small bubbles beneath the primary bubble.
38
Flow Boiling and Flow Condensation in Reduced Gravity
Issam Mudawar
- 01 Jan 2017
TL;DR: In this article, a review of published literature concerning reduced gravity flow boiling and flow condensation mechanisms and predictive tools that are crucial to the design of future space vehicles is presented, focusing on recent parabolic flight findings from NASA's Flow Boiling and Condensation Experiment (FBCE) and plans for insertion of the FBCE into the International Space Station.
36
Boiling in variable gravity under the action of an electric field: results of parabolic flight experiments
P. Di Marco,Rishi Raj,J. Kim +2 more
- 06 Dec 2011
Abstract: Results from the variable gravity pool boiling experiments performed during the 52nd ESA parabolic flight campaign are reported in this paper. During a typical parabola, the gravity acceleration changes from 1.8gE (high gravity) to ~0gE (low gravity) and finally back to 1.8gE. The two high gravity periods and the microgravity period are each roughly maintained for 20 seconds while the transition from high gravity to low gravity and vice versa occurs over a period of 3–5 seconds. Use of the high feedback frequency microheater array allowed quasi-steady boiling data over the continuous range of gravity levels (0gE-1.8gE). The experimental apparatus consisted of a boiling chamber with a 7×7 mm2 microheater array in a 10×10 configuration. Each heater in the array was individually controlled to maintain a constant temperature. The array could be operated in a full configuration or a selectively powered reduced set of 3×3 heaters. Experiments were performed with FC-72 as the test fluid, the pressure was maintained at a constant value between 1 and 1.13 atm and the subcooling ranged from 27 to 11 K. An external electric field was imposed over the boiling surface by means of a grid consisting of 4 rods, laid parallel to the surface; voltages up to 10 kV were applied. The electric field was effective in reducing the size of the detaching bubbles, and increasing the heat transfer compared to the values in low-g, although its effectiveness decayed as the heat flux/superheat increased. The current results compared well with previous results obtained in the ARIEL apparatus that was operated in orbital flight.
18
References
Pool Boiling Curve in Microgravity
TL;DR: In this article, a pool boiling experiment was conducted in the microgravity of space on a flat heater, consisting of a semitransparent gold film sputtered on quartz substrate, 19.05 x 38.1 mm (0.75 x 1.50 in).
79
Pool boiling curve in microgravity
Ho Sung Lee,Herman Merte,Francis P. Chiaramonte +2 more
- 01 Jan 1997
TL;DR: In this paper, a pool boiling experiment was conducted in the microgravity of space on a flat heater, consisting of a semitransparent gold film sputtered on quartz substrate, 19.05 x 38.1 mm (0.75 x 1.50 in).
26
Pool Boiling Phenomena in Microgravity
Ho Sung Lee,Herman Merte,Francis P. Chiaramonte +2 more
- 01 Aug 1998
22