Showing papers on "Subcooling published in 1979"
Patent•
21 Aug 1979TL;DR: In this paper, a mixture of gas rich in methane is liquefied by performing an auxiliary cycle and a main cycle in which are used an auxiliary and main refrigerating fluid of several components, in each cycle the compression, cooling, liquefying and sub-cooling of the refrigerating fluids in counter-flowing relationship with themselves after expansion-vaporization in a heat exchanger.
Abstract: Method of liquefying a mixture of gas rich in methane by performing an auxiliary cycle and a main cycle in which are used an auxiliary and a main refrigerating fluid of several components. In each cycle are performed the compression, cooling, liquefying and sub-cooling of the refrigerating fluids in counter-flowing relationship with themselves after expansion-vaporization in a heat exchanger. The gas to be liquefied is cooled in parallel with said main refrigerating fluid which has been pre-cooled in the auxiliary cycle. Pre-cooling of said gas is performed in an exchanger cooled by the refrigerating main fluid after its expansion-vaporization in said heat exchanging column of said main cycle and before its re-compression.
48 citations
46 citations
Patent•
20 Dec 1979
TL;DR: In this paper, a commercial refrigeration system of a type having at least one compressor, a suction header and a liquid header at a central location or machinery center, a condenser and a plurality of remotely located evaporators is described.
Abstract: Disclosed is a commercial refrigeration system of a type having at least one compressor, a suction header and a liquid header at a central location or machinery center, a condenser and a plurality of remotely located evaporators, wherein a suction-to-liquid heat exchanger is embodied in the suction header of the system and all of the relatively cool gaseous refrigerant returning to the central location from the remotely located evaporators is maintained in heat exchange contact with substantially all of the primary stream of relatively warm liquid refrigerant produced by the operation of the compressor and condenser. The large amounts of relatively warm liquid refrigerant and relatively cool gaseous refrigerant in heat exchange contact with one another enables the centrally located heat exchanger (1) to increase the suction gas temperature going into the suction side of the compressors, which increases their refrigerating capacity, and (2) to usefully sub-cool the liquid refrigerant before it is directed to the expansion valves in order to increase the refrigerant effect and efficiency of the system and cause a corresponding reduction in power requirements.
42 citations
TL;DR: In this paper, the generalized correlation of critical heat flux (CHF) derived by the author in previous studies is combined with the boiling length concept to make an analysis for obtaining theoretical predictions for the effect of inlet subcooling on CHF.
39 citations
TL;DR: In this article, photographic evidence of actual meh layer shapes was obtained to corroborate those inferred in [l], and photographs showed the melt Iayer both below and above the cylinder, thereby extending the results of [l] relevant to the role of natural convection in the melting of solids.
33 citations
TL;DR: In this article, an experimental study of subcooled and low quality film boiling for water in a vertical tube covering a mass flux range of 50−500 kg m−2 s−1 and an inlet subcooling range of 5−70°C is described.
24 citations
TL;DR: In this article, a violent pressure oscillation was observed in a vertical tube under a temperature gradient, and it was determined that the pressure was due to the existence of a large temperature gradient in the system, and that it occurred in the low temperature region of the system.
Abstract: In the subcooled decompression experiments of water in a vertical tube under a temperature gradient, a violent pressure oscillation was observed. By varying the gradient conditions it was ascertained that this pressure oscillation was due to the existence of the large temperature gradient in the system, and that it occurred in the low temperature region of the system. The generation of the pressure oscillation could be explained by assuming a reflection surface for the pressure wave caused by the blowdown. Two positions of the reflection surface were experimentally obtained from the structure of oscillatory pressure behavior and by computing the autocorrelation function of the pres- sure curve. In the system of a linearly descending temperature distribution, a flashing occurred partially and those two values were in good agreement with the position of the phase boundary generated just after the passage of the decompression wave. The conventional thermal equilibrium model could not completely explain this ...
8 citations
TL;DR: In this article, a physical model for the dynamics of vapour bubbles is presented, which is applicable to bubbles generated at the heated wall of channels with boiling flow, and it is shown that simultaneous agreement can be obtained with regard to bubble size, bubble lifetime and recondensation rate within the error band of experimental data by the proper choice of one fitting parameter only.
8 citations
TL;DR: In this paper, a theoretical study of film boiling on a sphere in forced convection is given, where the assumption is made that the sphere temperature is maintained constant and subcooling is included in the model.
7 citations
01 Jan 1979
6 citations
TL;DR: In this paper, the physical structure of a forced convection film boiling on a wedge has been investigated by means of two-phase boundary-layer theory and it has been shown that the effect of the pressure gradient in the liquid dominates the dynamics of the flow in the vapour layer.
Patent•
28 Sep 1979
TL;DR: In this paper, a conventional centrifuge refrigeration system is modified by connecting a capillary sized line between the expansion valve and the evaporator, which facilitates the easy removal of the expanders for repair and yet reduces icing of the expansion valves.
Abstract: A conventional centrifuge refrigeration system is modified by connecting a capillary sized line between the expansion valve and the evaporator. This permits the expansion valve to be located at a point within the centrifuge remote from the rotor. This facilitates the easy removal of the expansion valve for repair and yet reduces icing of the expansion valve. Further, the system capacity may be improved by wrapping the capillary line about the suction line to effect subcooling of the refrigerant before it passes to the evaporator. This enhances system capacity.
TL;DR: In this article, an experimental investigation of the peak nucleate boiling heat flux, during nitrogen pool boiling in a centrifugal force field, the maximum relative centrifugal acceleration of η = 2000 was attained.
TL;DR: The use of a modified Gardon-type heat flux meter for measuring the local boiling heat flux density around a large diameter horizontal cylinder which is quenched from a high temperature in saturated or subcooled water is described in this paper.
Patent•
24 Sep 1979
TL;DR: In this paper, the authors describe a refrigeration system that employs mechanical subcooling to substantially increase the efficiency of operation and reduce power consumption of a gaseous refrigerant.
Abstract: A refrigeration system employs mechanical subcooling to substantially increase the efficiency of operation and reduce power consumption The refrigeration system includes a compressor for compressing a gaseous refrigerant, a condenser for condensing the gaseous refrigerant and subcooling the liquid refrigerant, a receiver for receiving the liquid and a plurality of display cases having evaporators for evaporating the liquid refrigerant A supplemental subcooling system, including a subcooling evaporator associated with the receiver discharge further subcools the condensed refrigerant before it is passed to the display case evaporators The compressed gaseous refrigerant is first condensed at a condensing temperature of approximately 10° to 25° F above a preselected cooling temperature The condensed liquid is then mechanically subcooled if necessary to the preselected cooling temperature which should be preferably approximately 50° F
TL;DR: In this article, the authors show that the initial size and growth of the dryout patch significantly depends on the magnitude of the heat generation rate at the time of dryout, and they extend the correlation between saturated boiling and cooling at the bottom of the particulate bed.
Abstract: Data for the dryout heat fluxes in deep beds of volumetrically heated particles are obtained when the overlying liquid is subcooled or a certain prescribed cooling condition is applied at the bottom of the particulate bed. Semitheoretical correlations proposed earlier for saturated boiling in the particulate beds with insulated bottom have been extended to correlate the data with cooling at the bottom. Visual observation of the particulate bed after dryout indicates that initial size and growth of the dryout patch significantly depends on the magnitude of the heat generation rate at the time of dryout.
01 Jan 1979
TL;DR: In this paper, the authors reported the final test results for the five 1 MWt shell-and-tube heat exchangers tested at Argonne National Laboratory ( Argonne Lab).
Abstract: Final test results are reported for the five 1 MWt shell-and-tube heat exchangers tested at Argonne National Laboratory These five heat exchangers are the Union Carbide flooded-bundle evaporator, the Union Carbide sprayed-bundle evaporator, the Union Carbide enhanced-tube condenser, the Carnegie-Mellon vertical fluted-tube evaporator, and the Carnegie-Mellon vertical fluted-tube condenser Performance parameters measured include the overall heat transfer coefficient (U/sub 0/), the water-side pressure drop, and the vapor quality Also measured were operational characteristics of the heat exchangers such as repeatability of results and the dependence of U/sub 0/ on heat duty, ammonia flow rate, and subcooling Individual water-side and ammonia-side coefficients were deduced using the Wilson Plot method
TL;DR: In this article, the authors applied dimensional analysis to the partial penetration data on the Battelle models (1 15 and 2 15 scales) results in a better fit of the penetration data than previous correlations, which predicts the fractional penetration of ECC water into the lower plenum from the water flow rate, liquid sub cooling and system pressure, in terms of Froude numbers based on superficial velocities of steam and water.
TL;DR: In this paper, the initial course of a postulated accident scenario in an LMFBR, involving the rupture of all piping connected to the reactor vessel, in the event of an earthquake (or an equivalent scenario involving both loss of heat removal and system rupture), is examined.
TL;DR: In this article, minimum film boiling temperature data obtained on 19- and 25-mm-diam spheres quenched in subcooled water are used to establish a relationship between the temperature of the hot molten material and...
Abstract: Minimum film boiling temperature data obtained on 19- and 25-mm-diam spheres quenched in subcooled water are used to establish a relationship between the temperature of the hot molten material and ...
TL;DR: In this paper, the authors present an analysis for transients of clad surface temperature and quench front and show that film boiling is the predominant heat transfer during the reflood portion in LOCA.
Abstract: This study presents analysis for transients of clad surface temperature and quench front. It was said that film boiling which occurs on the wall surface above the quench front was a predominant heat transfer during the reflood portion in LOCA. Comparison of experimental results with analysis indicated that the heat transfer for the film boiling was correlated considering the effect flooding speed as follows : [numerical formula]
TL;DR: In this article, it is shown that the film boiling instability is a mechanical phenomenon arising from the vapor-liquid interface and it is dragged by the liquid boundary layer, and the total velocity of propagation is the algebric sum of a dragging velocity common to the liquid and the vapor at the interface.
Patent•
13 Sep 1979
TL;DR: In this article, a method for operating a refrigeration system without reverse cycle defrost is presented. But the method is not suitable for the case where the heat exchanger is divided into a plurality of zones, one zone being constantly utilized as a subcooler to both defrost said zone and to subcool the refrigerant.
Abstract: Apparatus and a method for operating a refrigeration system without reverse cycle defrost are disclosed. A heat exchanger is divided into a plurality of zones, one zone being constantly utilized as a subcooler to both defrost said zone and to subcool the refrigerant. The remaining zones of the heat exchanger are utilized as an evaporator as is known in the art. A selector valve which is capable of indexing liquid refrigerant flow between zones and receiving gaseous refrigerant from the remaining zones is also disclosed. Additionally, a header arrangement having both expansion means and a conduit controlled by check valve is utilized to direct refrigerant flow from the subcooled zones to the remaining zones of the heat exchanger which act as an evaporator.