Core Flow Rate Research Articles

In-situ oxidation of crude oils for enhanced recovery by alkaline flooding

Crude oils with acid numbers too low to warrant alkaline flooding for enhanced oil recovery were subjected to in-situ air oxidation in unconsolidated cores at temperatures corresponding to reservoir conditions. The oxidation process resulted in a significant increase in the acid number of the crudes studied. Acid numbers were found to increase with temperature, air flow rate, pressure, and reaction time and were found to be affected by the core and crude composition. The range of conditions studied include temperatures of 75–125 °C, pressures of 0.34–3.10 MPa [50–450 psig], reaction times of 24–504 h and core flow rates of 0–1.41 m h −1 (0–111 ft day −1). Oxidized crudes were found to have much lower caustic/crude interfacial tensions than the parent crude. Flooding experiments in unconsolidated cores showed an improved recovery efficiency for an oxidized crude over its parent crude.

Examination of gas-liquid flow in a Venturi scrubber

Liquid core and wall film flow rates have been measured in a pilot plant scale Venturi scrubber of Pease-Anthony design for liquid-to-gas flow ratios varying between 3 and 14 U.S. gal of H/sub 2/O/1000 SCF of air. The gas throat velocities were 150, 200, and 250 ft/s. The initial momentum of the injected scrubbing liquid has been found to be an important parameter in defining the maldistributions of liquid throat coverage. Experimental results have been compared to predictions from a two-dimensional model accounting for initial liquid momenta an turbulent diffusion.

Simple Method to Predict Power Level and Core Flow Rate of Boiling Water Reactors by Using One-Point Core Model

A simple one-point core model has been developed to predict startup and load following features of boiling water reactors (BWRs). The variables used in this model are core thermal power, core flow rate, xenon concentration and control rod pattern, where the last variable is expressed in terms of the corresponding thermal power at the rated core flow. The number of parameters to be identified is only three, and they are determined by flow control line, xenon reactivity coefficient and power reactivity coefficient. These parameters can be adjusted by using the actual operating data of BWR plants. The accuracy of the one-point core model was evaluated in some typical startup operations of a reference 800 MWe class BWR. The prediction errors of the model were within 2% of relative power in comparison with results of a three-dimensional BWR core simulator and within 3% in comparison with the operating data. Use of this one-point core model, with xenon-iodine maps, should successfully predict reactor conditions, even when employing only simple hand-calculations.

On-Line Test of Power Distribution Prediction System for Boiling Water Reactors

A power distribution prediction system for boiling water reactors has been developed and its on-line performance test has proceeded at an operating commercial reactor. This system predicts the power distribution or thermal margin in advance of control rod operations and core flow rate change. This system consists of an on-line computer system, an operator's console with a color cathode-ray tube, and plant data input devices. The main functions of this system are present power distribution monitoring, power distribution prediction, and power-up trajectory prediction. The calculation method is based on a simplified nuclear thermal-hydraulic calculation, which is combined with a method of model identification to the actual reactor core state. It has been ascertained by the on-line test that the predicted power distribution (readings of traversing in-core probe) agrees with the measured data within 6% root-mean-square. The computing time required for one prediction calculation step is less than or equal to 1.5 min by an HIDIC-80 on-line computer.

Simple method to predict power level and core flow rate of boiling water reactors by using one-point core model.

A simple one-point core model has been developed to predict startup and load following features of boiling water reactors (BWRs). The variables used in this model are core thermal power, core flow rate, xenon concentration and control rod pattern, where the last variable is expressed in terms of the corresponding thermal power at the rated core flow. The number of parameters to be identified is only three, and they are determined by flow control line, xenon reactivity coefficient and power reactivity coefficient. These parameters can be adjusted by using the actual operating data of BWR plants. The accuracy of the one-point core model was evaluated in some typical startup operations of a reference 800 MWe class BWR. The prediction errors of the model were within 2% of relative power in comparison with results of a three-dimensional BWR core simulator and within 3% in comparison with the operating data. Use of this one-point core model, with xenon-iodine maps, should successfully predict reactor conditions...

Flow through brushborders and similar protuberant wall structures.

Longitudinal flow through channels with protuberant wall structures such as brushborders were studied both experimentally and theoretically. The experiments were performed using tubes with synthetic internal brushborders, scaled to resemble the geometry and flow in proximal tubules of the kidney. Fractional flow rates in the brushborder were deduced from transit times of dye traces through the central core and total flow rate. The measured ratios of brushborder to core flow QB/QC were found to be independent of Reynolds number over the range Re = 0.01 - 0.2. They agreed reasonably well with theoretical predictions based on the Kozeny-Carman equation for flow through arrays of parallel cylinders. The predictions can be extended to arbitrary geometries and turbulent flow conditions by appropriate modifications. Extrapolation of the results to the proximal tubule of the kidney indicate that brushborder flowrates there vary from 0.003 to 0.09% of total flow. Any axial transport in these structures would be predominantly diffusive in nature, and would be highly unlikely to affect radial brushborder gradients and transmural flux.