Showing papers on "Subcooling published in 1969"

Low ambient control of subcooling control valve

Abstract: A refrigeration system has a condenser coil cooled by outdoor air, and has a subcooling control valve with its thermal bulb in heat exchange contact with the liquid line from the condenser coil. The bulb is normally heated by an electric heater, and the valve is adjusted to provide a desired amount of subcooling of the liquid when the heat applied to the bulb by the electric heater is maximum. At low outdoor temperatures when the condenser pressure decreases so that a conventional subcooling control valve would not open sufficiently, the electric heat is automatically reduced so that the valve opens wider.

Refrigeration cycle for the aliquefaction of natural gas

Abstract: In the liquefaction of natural gas wherein the refrigeration cycle fluid contains natural gas components, and such components are subjected to fractional condensation to obtain different temperature levels of refrigeration, the system is improved by adjusting the C3-C6 content of cycle fluid and the pressure of at least one intermediate pressure stage of the circulation pressure in such a manner that condensate is formed in the corresponding intercooler of said pressure stage. This condensate is then separated and subjected to heat exchange to utilize its refrigeration values and recirculated to the circulation compressor via an expansion valve. In this way, a substantial concentration of heavy hydrocarbons can be utilized to increase the refrigeration capacity of the refrigeration cycle, but said hydrocarbons do not deleteriously affect the lower temperature levels of refrigeration.

Hydrodynamic Instability in a Full-Scale Simulated Reactor Channel:

Abstract: An experimental programme has been carried out to investigate parallel-channel instability in a full-scale simulated nuclear reactor channel operating in vertical high-pressure boiling-water upflow. Experimental data have been obtained using a vertically mounted test section containing two 19-rod electrically heated bundles with a total heated length of 195 in. The test section was operated in parallel with an unheated by-pass between common inlet and outlet headers. The characteristics of the observed test-section and by-pass flow oscillations are described in detail. Data are presented showing the effect upon test section flow stability of bundle electrical power, inlet subcooling, operating pressure, feeder pressure loss coefficients and the ratio of by-pass flow-rate to test-section flow-rate.

A correlation of subcooled-boiling pressure drop for low-pressure water flowing in tubes with constant heat flux

Abstract: One dimensional flow model to correlate subcooled boiling pressure drop in circular tubes with constant heat flux

Separation of air utilizing a closed-cycle helium refrigeration system

Abstract: IN THE SEPARATION OF OXYGEN AND NITRONGEN FROM AIR, THE PROCESS INVOLVING INTRODUCING COMPRESSED COOLED AIR AT ITS SATURATION TEMPERATURE INTO A FRACTIONATING COLUMN, PASSING ANOTHER GASEOUS MEDIUM SUCH AS HELIUM INTO HEAT EXCHANGE RELATION ALONG THE LOWER PORTION OF THE FRACTIONATING COLUMN, THE HELIUM BEING AT A TEMPERATURE TO SUPPLY HEAT ALONG THE LOWER PORTION OF THE COLUMN, COOLING THE RESULTING HEATED HELIUM, PREFERABLY BY HEAT EXCHANGE WITH AN EXTERNAL REFRIGERANT FOLLOWED BY WORK EXPANSION OF THE HELIUM, PASSING THE COOLED HELIUM GAS INTO HEAT EXCHANGE RELATION ALONG THE UPPER PORTION OF THE COLUMN, SUCH HELIUM BEING AT A TEMPERATURE TO REMOVE HEAT ALONG THE UPPER PORTION OF THE COLUMN, COMPRESSING THE EXCITING HELIUM AND RECYCLING SAME IN HEAT EXCHANGE RELATION ALONG THE LOWER PORTION OF THE COLUMN THUS EFFECTING A DIFFERENTIAL DISTILLATION OF THE AIR IN THE COLUMN AND SEPARATING NITROGEN OVERHEAD FROM THE UPPER END OF THE COLUMN AND LIQUID OXYGEN FROM THE LOWER END OF THE COLUMN. IN THE PREFERRED PROCEDURE, NITROGEN OVERHEAD IS PASSED IN HEAT EXCHANGE RELATION WITH COMPRESSED FEED AIR FOR COOLING SAME, A PORTION OF THE HEATED NITROGEN GAS IS COMPRESSED AND COOLED, AND SUCH COOL COMPRESSED NITROGEN PASSED IN HEAT EXCHANGE RELATION WITH LIQUID OXYGEN WITHDRAWN FROM THE BOTTOM OF THE COLUMN, COOLING THE COMPRESSED NITROGEN AND VAPORIZING THE OXYGEN, WHICH IS WITHDRAWN AS PRODUCT, THE COOLED NITROGEN IS PASSED IN HEAT EXCHANGE RELATION WITH THE LOWER PORTION OF THE COLUMN, IS SUBCOOLED BY HEAT EXCHANGE RELATION WITH NITROGEN OVERHEAD WITHDRAWN FROM THE COLUMN, IS THROTTLED, AND THE RESULTING NITROGEN INTRODUCED AS REFLUX TO THE TOP OF THE COLUMN. THE SYSTEM HAS THE ADVANTAGE OF EMPLOYING A SINGLE FRACTIONATING COLUMN OPERATING AT OR SLIGHTLY ABOVE ATMOSPHERIC PRESSURE, WITH REDUCED POWER CONSUMPTION AND INCREASED EFFICIENCY, THE ONLY GAS REQUIRING SIGNIFICANT COMPRESSION BEING THE PORTION OF THE GASEOUS NITROGEN WITHDRAWN FROM THE UPPER END OF THE COLUMN AND RECYCLED TO PROVIDE ADDITIONAL REFLUX TO THE COLUMN.

Nondimensional Expression for the Relation between Pressure Drop and Flow Rate in Steam Generating Tubes

Abstract: A method to express the relationship between pressure drop and flow rate in steam generating tubes is presented. The characteristics of the pressure drops is represented in nondimensional generalized forms. In a case of uniform heat flux along a tube, it is given by the following equation : ΔP*=2/1κξ3+(1-κ)ξ2+2/1κξ Here, ΔP*=nondimensional pressure drop defined in this report, ξ=nondimensional flow rate, υ"=specific volume of saturated steam, υ'=specific volume of saturated water, r0=subcooling, r=latent heat of evaporation, κ={(υ"/υ')-1}r0/r. The charts in cases of various heat flux distributions along tubes are showm. They can be used to study the influence of each factor such as pressure, subcooling and heat flux distribution and so on characteristics of pressure drop and to estimate the flow stability and the distribution of flow rates in parallel tubes.

Two-Phase Critical Flow under Diabatic Conditions

Abstract: This paper summarizes an experimental investigation of steam-water critical flow in heated tubes. A wide range of data was taken for water at pressures below 100 lbf/in2 (abs.) in tubes of small diameter. It is demonstrated that critical flow conditions can occur in subcooled boiling at low exit subcoolings. At equilibrium qualities below about 0·04, the data differ significantly from adiabatic data for a similar exit geometry. The deviations can be explained in terms of the additional non-equilibrium effects present in heated flows. For higher qualities, the diabatic data are in good agreement with adiabatic data, and can be approximately predicted by a slip equilibrium model.