Showing papers on "Boiling published in 1985"
TL;DR: In this paper, a thermodynamic model of boiling hydrothermal solutions is developed and applied over a wide range of physical and chemical conditions, and it is shown that boiling is the most generally effective ore depositional mechanism at the conditions operative in many natural boiling hydroglobal systems.
Abstract: A thermodynamic model of boiling hydrothermal solutions is developed and applied over a wide range of physical and chemical conditions. Within the range of conditions observed in natural boiling hydrothermal systems the processes of liquid-vapor partitioning and the resultant effects on mineral solubilities are highly varied and complex. Metals that are complexed by chloride are deposited largely as a result of the decreasing proton concentration associated with CO 2 exsolution during boiling. Metal bisulfide complexes are destabilized most when the decrease in proton concentration is sluggish relative to the loss of H 2 S.Vaporization of only a few percent of a solution can decrease the proton concentration by several orders of magnitude when the CO 2 /H (super +) and CO 2 /Sigma SO 4 concentration ratios are initially high. The relationship between the proton, CO 2 , and Sigma SO 4 concentrations prior to boiling to the proton concentration after boiling is defined explicitly by a few simple equations. These equations along with the solubilities of calcite and anhydrite constitute the chemical boundary conditions for significant mineral deposition by boiling. Typical hydrothermal fluids lose most of their volatile components to the vapor phase and most of their metals to mineral phases by the time boiling has proceeded to the point where the volumes of the vapor and liquid phases are equal.Physical variables such as the heat budget and the restrictions on the partitioning of mass between liquid and vapor, although significant, are subordinate to the compositional variables in determining the chemical evolution of a boiling hydrothermal solution. Mineral deposition is most vigorous when the volatile components partition from the solution to the vapor phase in a manner resembling perfect fractional (Rayleigh) distillation. As temperature decreases, the efficiency of boiling for depositing metals from solution increases, and the amount of metals in solution typically decreases such that the net effect of boiling is most favorable for ore formation at temperatures around 300 degrees C. Mineral and metal complex stoichiometries in combination with the relative volatilities of CO 2 and H 2 S determine the general sequence of mineral deposition during boiling. These major variables, many other minor variables, and the multiple interactions thereof are accounted for rigorously. The amount and paragenesis of ore and gangue minerals deposited by boiling are presented for numerous hypothetical hydrothermal systems. Analysis of these results suggests that boiling is perhaps the most generally effective ore depositional mechanism at the conditions operative in many boiling hydrothermal systems.
638 citations
TL;DR: This article showed that contact angle has a very strong influence on transition boiling, improved wetting giving increased heat flux at a given superheat, provided a consistent method is used to roughen the surface then roughening improves the nucleate boiling heat transfer.
132 citations
TL;DR: In this paper, the wall temperature profile and photographic observation were performed for R-113 subcooled boiling flow in a channel with heat fluxes up to the CHF, and the bubble density on the heated surface increases and remarkably large coalescent bubbles appear periodically near the heating section outlet.
100 citations
TL;DR: In this article, a quasilinear Hopf-bifurcation analysis of the marginal stability boundary of a uniformly heated boiling channel is presented. But the analysis is restricted to the case when the effects of gravity and friction are considered.
Abstract: Thermally induced flow instabilities in uniformly heated boiling channels have been studied analytically. The classical homogeneous equilibrium model was used. This distributed model was transformed into an integrodifferential equation for inlet velocity. A linear analysis showed interesting features (i.e. islands of instability) of the marginal stability boundary which appear when the effects of gravity and friction were systematically considered. A quasilinear Hopf-bifurcation analysis, valid near the marginal-stability boundaries, gives the amplitude and frequency of limit-cycle oscillations that can appear on the unstable side of the boundary. The analysis also shows cases where a finite-amplitude perturbation can cause a divergent instability on the stable side of the linear-stability boundary.
98 citations
Patent•
12 Jun 1985
TL;DR: Improved heat transfer tube and method of making same has mechanical enhancements which can individually improve either the inner or outer surfaces or which can cooperate to increase the overall efficiency of the tube as discussed by the authors.
Abstract: Improved heat transfer tube and method of making same has mechanical enhancements which can individually improve either the inner or outer surfaces or which can cooperate to increase the overall efficiency of the tube The internal enhancement, which is useful on either boiling or condensing tubes, comprises a plurality of closely spaced helical ridges which provide increased surface area and are positioned at an angle which gives them a tendency to swirl the liquid The external enhancement, which is applicable to boiling tubes, is provided by successive cross-grooving and rolling operations performed after finning The finning operation, in a preferred embodiment for nucleate boiling, produces fins while the cross-grooving and rolling operation deforms the tips of the fins and causes the surface of the tube to have the general appearance of a grid of generally rectangular flattened blocks which are wider than the fins and separated by narrow openings between the fins and narrow grooves normal thereto The roots of the fins and the cavities or channels formed therein under the flattened fin tips are of much greater width than the surface openings so that the vapor bubbles can travel outwardly through the cavity and to and through the narrow openings The cavities and narrow openings and the grooves all cooperate as part of a flow and pumping system so that the vapor bubbles can readily be carried away from the tube and so that fresh liquid can circulate to the nucleation sites The rolling operation is performed in a manner such that the cavities produced will be both larger and smaller than the optimum minimum pore size for nucleate boiling of a particular fluid under a particular set of operating conditions
85 citations
Patent•
25 Mar 1985
TL;DR: In this paper, a liquid egg falls gently from only a small height onto the surface of liquid nitrogen and is prevented from freezing up by a flow of ambient or heated air over it.
Abstract: Chilling or freezing a substance into small pellets is disclosed. A substance such as liquid egg falls gently from only a small height onto the surface (12) of liquid nitrogen. The discharge nozzle (13) is prevented from freezing up by a flow of ambient or heated air over it. The surface of the boiling nitrogen is kept smooth by imparting a velocity to the nitrogen with an impeller (20) or by running the nitrogen along a trough. The pellets are consistent as to final temperature, and the process is efficient as to nitrogen use. The process can be used with other thick, creamy substances.
81 citations
Patent•
18 Feb 1985TL;DR: The low temperature properties of a distillate petroleum fuel oil boiling in the range 120° C. to 500° C, and whose 20% and 90% distillation points differ by less than 100° C., and/or whose Final Boiling Point is at least 340° C to 370° C as discussed by the authors are improved by the addition of a polymer or copolymer having at least 25 wt. % of n-alkyl groups of average number of carbon atoms from 12 to 14 with no more than 10.
Abstract: The low temperature properties of a distillate petroleum fuel oil boiling in the range 120° C. to 500° C., and whose 20% and 90% distillation points differ by less than 100° C., and/or whose Final Boiling Point is in the range 340° C. to 370° C. are improved by the addition of a polymer or copolymer having at least 25 wt. % of n-alkyl groups of average number of carbon atoms from 12 to 14 with no more than 10 wt. % containing more than 14 carbon atoms.
72 citations
TL;DR: In this paper, an experiment with water flowing in a round tube at atmospheric pressure was performed to study critical heat flux (CHF) at low mass velocities, flow stagnation and flow reversal conditions.
70 citations
TL;DR: In this article, a transfert de chaleur a pelliculaire en convection naturelle de liquides satures sur une surface verticale isotherme is discussed.
Abstract: Etudes experimentale et theorique du transfert de chaleur a l'ebullition pelliculaire en convection naturelle de liquides satures sur une surface verticale isotherme
68 citations
TL;DR: In this paper, microconvective, instability, experimental, and correlational aspects of subcooled flow boiling critical heat flux (CHF) are summarized, and the present understanding of CHF in sub cooled flow boiling is presented.
Abstract: Microconvective, instability, experimental, and correlational aspects of subcooled flow boiling critical heat flux (CHF) are summarized. The present understanding of CHF in subcooled flow boiling i...
TL;DR: In this paper, the results of fast transient boiling tests using rapidly heated platinum wires immersed in water were presented, showing that very fast heating resulted in spontaneous nucleation on the wire surface and exceptionally high rates of heat transfer.
1 Jan 1985
TL;DR: In this paper, the authors applied the technique of using a microthermocouple flush mounted at the boiling surface for the measurement of the local surface-temperature history in film and transition boiling on high temperature surfaces.
Patent•
14 Oct 1985
TL;DR: In this paper, the main working fluid is expanded to a low pressure level to convert energy to a usable form, and the spent low-pressure level working fluid are condensed by dissolving with cooling in the lean solution to regenerate an initial working fluid for reuse.
Abstract: A method and apparatus (10) for implementing a thermodynamic cycle involves utilizing partial distillation of a multi- component working fluid stream. At least one main enriched solution is produced which is relatively enriched with respect to the lower boiling temperature component, together with at least one lean solution which is relatively impoverished with the respect of lower boiling temperature component. The main working fluid is expanded (104) to a low pressure level to convert energy to a usable form. This spent low pressure level working fluid is condensed (126) by dissolving with cooling (106) in the lean solution to regenerate an initial working fluid (1) for reuse. A portion of the impoverished fraction may be injected (139) into the charged gaseous main working fluid in order to obtain added work and to increase system efficiency by decreasing the temperature of the output fluid flow when the fluid flow would otherwise have been superheated. A low pressure, low temperature expanded spent fluid may be distilled using low quality heat to create an enriched solution which has a significantly higher concentration of the lower boiling component. For this enriched solution, a reduced temperature and pressure is sufficient to enable distillation. The efficiency of the cycle may be enhanced by charging (120) the spent fluid with the lower boiling temperature component prior to distillation. This may be accomplished by lowering the pressure of the impoverished fraction to separate (118) an additional lower boil- . ing temperature fraction.
Patent•
26 Apr 1985TL;DR: In this paper, a heat transfer apparatus characterized in that a heat conductive member which has a plurality of layers of cavity groups and apertures for bringing the cavity groups into communication is installed on a surface of each of the heat generating bodies.
Abstract: In an apparatus wherein heat generating bodies such as integrated circuit chips are cooled by utilizing boiling of a liquid; a heat transfer apparatus characterized in that a heat conductive member which has a plurality of layers of cavity groups and apertures for bringing the cavity groups into communication is installed on a surface of each of the heat generating bodies.
TL;DR: In this paper, a method of measuring liquid-solid contact in boiling is described, where the heat transfer surface is coated with a thin, electrically-insulating layer and the impedance between the metal substrate and the boiling liquid is measured.
1 Sep 1985
TL;DR: In this paper, a new correlation predicting critical heat flux (CHF) for a saturated forced convective boiling with an impinging jet was introduced, which is able to predict all the CHF data in V-regime with a good accuracy of +-20% to which the correlations existing until now could not be applicable for 15 36.
Abstract: The present study introduces a new correlation predicting critical heat flux (CHF) for a saturated forced convective boiling with an impinging jet. The new correlation is able to predict all the CHF data inV-regime with a good accuracy of +-20% to which the correlations existing until now could not be applicable for 15 36. The new correlation seems to support a new criterion of CHF mechanism applicable for not only pool boiling but also forced convective boiling, recently proposed by Katto and Haramura.
TL;DR: In this article, the cooling effect of coolant is measured and the fraction of mechanical energy conducted as heat into the workpiece is estimated by Jaeger's moving heat theory extended to include cooling effect.
Abstract: This paper aims to clarify workpiece temperature and the mechanism of grinding burn in creep feed grinding. The workpiece is modelled thermally by a three dimensional finite element method. The cooling effect of coolant is measured and the fraction of mechanical energy conducted as heat into the workpiece is estimated by Jaeger's moving heat theory extended to include the cooling effect. The analytical results are shown to agree well with the experimentally obtained temperature distribution. From the experimental evidence that the onset of grinding burn is closely related to the boiling of the coolant used, the mechanism of the grinding burn can be considered as follows; when the grinding zone temperature reaches a point at which bubbles begin to form, the bubbles grow up rapidly in the wheel-workpiece interface and block heat transfer to the coolant. This is verified by the above-mentioned thermal mode.
17 Feb 1985
TL;DR: In this paper, the authors analyzed the pool boiling problem in cavities from the point of heat transfer by dividing the solution domain into three rectangular regions which are connected through the interface boundary conditions in the form of compatibility and the continuity relationships.
Abstract: The pool boiling problem in cavities is analyzed from the point of heat transfer by dividing the solution domain into three rectangular regions which are connected through the interface boundary conditions in the form of the compatibility and the continuity relationships. The numerical solution is accomplished by using the method of differential quadrature.
TL;DR: In this article, a theoretical study has been conducted to investigate an earlier transition from the film to the transition boiling, which may occur during the rapid cooldown of hot metals coated with a thin layer of insulating (low thermal conductivity) material.
TL;DR: In this article, the effects of fluid properties, pool subcooling, crevice length, and gap size on the boiling behavior and critical heat flux (CHF) were studied.
Abstract: Experimental results of the pool boiling in horizontal narrow annuli are reported. The effects of fluid properties, pool subcooling, crevice length, and gap size on the boiling behavior and the critical heat flux (CHF) are also studied. The CHF decreases with decreasing gap size or increasing length of the annuli. The lower CHF of narrow crevices may be explained by the thin film evaporation. A semi-empirical correlation is established for the CHF of pool boiling in horizontal confined spaces. This correlation is compared with the CHF data of the present experiment. Satisfactory agreement is obtained.
TL;DR: In this article, the authors examined the explosive synthesis of diamond powders and some of the properties of the products, which were made at the pressures and temperatures indicated in a phase diagram.
Abstract: This paper studies the explosive synthesis of diamond and some of the properties of the products. Some properties of ultrafine diamond powders are examined which were made at the pressures and temperatures indicated in a phase diagram. Particular attention was given to the phase composition of the powder and to the sizes of the diamond particals. The properties of the powders were examined after boiling the synthesis products in perchloric acid for 2 h and then repeatedly washing the products with water and drying them. For comparison, an illustration shows the pattern from diamond of grade ASM 5/3; 3/2 made under static conditions. To determine the proportion of diamond in the powders obtained after enrichment, a graph was constructed as the ratio of the integral intensities of the line for diamond and the line for graphite as a function of diamond content in a diamond-graphite mixture. The calibration curve was based on spectrally pure graphite and ASM 5/3; 3/2 diamond powder.
TL;DR: In this paper, the chromatographic behavior of n-pentane, n-butane, isobutane and propane was studied in the liquid, gaseous and supercritical Gaseous states by running chromatograms of a mixture of polynuclear aromatic hydrocarbons.
TL;DR: In this paper, the sensory hairs of the silkmoth, Bombyx mori, are used to check recrystallization and secondary freezing damage in a biological object, because cryofixation by immersion into propane (90 K) routinely yields well-preserved specimens without noticeable freezing damage.
Abstract: SUMMARY
The sensory hairs of the silkmoth, Bombyx mori, are suitable test objects to check for recrystallization and secondary freezing damage in a biological object, because cryofixation by immersion into propane (90 K) routinely yields well-preserved specimens without noticeable freezing damage. After rewarming the frozen specimens for 10 min to 230 K (boiling propane), the tissue preservation has not deteriorated, and even after 45 min at 230 K, ice-crystal ghosts rarely exceed 50 nm. Two minutes at 250 K (in deep freezer) produced moderate freezing damage with ice-crystal ghosts of 30–75 nm, whereas 90 min at 250 K resulted in severe damage with ice-crystal ghosts well over 100 nm. Secondary freezing damage by ice-crystal growth upon rewarming well-frozen biological specimens, therefore, is a relatively slow process, depending not only on the temperature, but also on the exposure time. Moreover, with some biological specimens, secondary ice-crystal growth starts at much higher temperatures than previously guessed, and with short exposure times rarely should become a hazard in fine structure work.
TL;DR: In this paper, the theoretical Rankine power cycle efficiency ηR and the pressure ratio (PR) are determined automatically for a given working fluid, and the only way that the values of (R and PR) can be varied is to choose another working fluid.
Patent•
22 Apr 1985TL;DR: In this article, a heat-regenerative, expander-cycle, turbine-drive rocket engine is described, in which heated oxidizer gas is used to drive the fuel and oxidizer turbines.
Abstract: A heat-regenerative, expander-cycle, turbine-drive rocket engine 26 in which heated oxidizer gas is used to drive the fuel and oxidizer turbines 16 and 20. The hot exhaust gas from the oxidizer turbine 20 is passed through a heat-donor coil 36 of a heat exchanger 24 where it passes heat to the oxidizer flowing through a donee coil 34 to preheat the oxidizer liquid and gasify it before it is passed through the cooling jacket 28 of the rocket engine 26 where it cools the engine 26 and is itself heated to a higher temperature. The oxidizer, e.g., N2 O4, is brought to higher temperature and pressure than its supercritical temperature and pressure so that flashing and boiling of the oxidizer are avoided.
Patent•
23 May 1985
TL;DR: In this paper, the heavy and volatile hydrocarbons are mechanically separated from the water, by means of a thermal degassing, and the low boiling and non-condensable hydrocarbs are separated in a shower evaporation step with downstream vapor compression.
Abstract: A process for the continuous production of boiler feed water from process waters in the oil extraction industry during which salts and hydrocarbons are removed from the water, without Fe ++ precipitating. The heavy hydrocarbons are mechanically separated, the volatile hydrocarbons are separated from the water, by means of a thermal degassing, and the low boiling and the non-condensable hydrocarbons are separated in a shower evaporation step with downstream vapor compression, wherein the low boiling non-condensable hydrocarbons are evaporated with the waste water within the shower evaporator and the non-condensable hydrocarbons then are drawn off from a downstream separator. A salt-free oxygen-free pure water is removed from a separator.