Flow-through-screen tests

The purpose of this chapter is to present the experimental results for the full-scale LAD outflow tests in liquid hydrogen. Test conditions were taken over a wide range of liquid temperatures (20.3-24.2 K), tank pressures (100-350 kPa), and outflow rates (0.010-0.055 kg/s) thermally and operationally representative of an in-space propellant transfer from a depot storage tank or to a smaller scale in-space engine. Horizontal LAD tests were conducted to measure independently the frictional and dynamic losses down the channel. Flow-through-screen tests were performed to measure independently the dominate pressure loss in LEO, the FTS resistance. Meanwhile, 1-g inverted vertical LAD outflow tests were conducted to obtain performance data for two full-scale 325 x 2300 LAD channels. One of the channels had a perforated plate and a custom-built internal thermodynamic vent system to enhance performance. Model predictions from Chapter 3 are compared to each set of experimental data. 

FIGURE 9.13 Typical Flow-through-Screen Test Run for the 325 x 2300 and 450 x 2750 Screen Samples in Liquid Hydrogen. Lines are model generated curves using Equation (3.33). 

The purpose of the flow-through-screen (FTS) tests was to measure the FTS pressure loss associated with liquid flow through a LAD screen in LH2. While the FTS pressure drop is second order in 1-g, it becomes the dominate pressure loss in flight, in LEO where hydrostatics are minimal. Therefore, experiments are required to determine the magnitude of this contribution as well as validate the FTS model from Chapter 3. 

We have developed and tested a metabolism system and regimen which allows collection of data comparable to those from terrestrial animals. The key to our experiments is a metabolism chamber, described previously Cl3, 14) CFig. 1), which can be operated in either the static or flow-through mode. Briefly, individuals or groups of animals are held at constant temperature in the jacketed glass chamber (A), on a stainless steel screen (B), while pure water or test solution is passed over them (or held under static conditions). Solid wastes are separated in a jacketed container (C) held near 0°C to minimize microbial action, and the effluent containing dissolved metabolites is passed onto a column of nonionic macroreticular adsoprtion resin where organic solutes are adsorbed from solution (D). 

Fuel is cooled to the test temperature through a predetermined temperature sequence and is then caused to flow through a length of copper tubing and filter screen similar to that found in full-scale fuel handling equipment. The rate at which the fuel flows and the volume... 

In addition, a secondary screening HT method is well suited to test the catalytic properties of materials using a parallel flow-through reactor system (i.e. the Multi Fixed Bed Reactor System—MFBR) fitted with parallel detection and quantification techniques by MS and GC [32-35],... 

Tertiary oil was increased up to 41% over conventional CO2 recovery by means of mobility control where a carefully selected surfactant structure was used to form an in situ foam. Linear flow oil displacement tests were performed for both miscible and immiscible floods. Mobility control was achieved without detracting from the C02-oil interaction that enhances recovery. Surfactant selection is critical in maximizing performance. Several tests were combined for surfactant screening, included were foam tests, dynamic flow tests through a porous bed pack and oil displacement tests. Ethoxylated aliphatic alcohols, their sulfate derivatives and ethylene oxide - propylene oxide copolymers were the best performers in oil reservoir brines. One sulfonate surfactant also proved to be effective especially in low salinity injection fluid. 

Use of surfactants may prove to be a good technique for separating diesel fuel fit>m a soil as indicated in results obtained in preliminary screening tests (removal efficiencies up to 97%) and from results of other studies performed on laboratory-packed soil columns (removal efficiencies up to 8.6%), assuming flow through the bulk matrix. Results presented here using undisturbed, diesel-fuel-contaminated soil cores taken from a site indicate, however, that removal of diesel fuel from the soil flooded with surfactant solution was generally less than 1%. Low removal efficiencies in these soil... 

It has been reported that a DNA wrapped carbon nanotube device can change firom metallic behavior in dry conditions to semiconductor behavior in wet conditions [12]. Ouellette [13] analyzed the time evolution of electrical current in a suspended carbon nanotube positioned in a microfluidic channel through which DNA molecules were allowed to flow. Electrical spikes were observed when DNA molecules were present in the microfluidic channel DNA molecules constantly flowed through the microfluidic channel and electrostatic screening of van der Waals interaction due to ions was minimized. Spikes current levels are below or above the original CNT current level depending on the type of DNA molecule tested. 

In order to resolve the above-mentioned problems, perforated wall structures have been introduced especially in small craft harbors. The simplest perforated wall structure may be a curtain-wall breakwater (sometimes called wave screen or skirt breakwater), which consists of a vertical wall extending from the water surface to some distance above the seabed. Recently, Isaacson et al." proposed a slotted curtain-wall breakwater. Another simple perforated wall structure may be an array of vertical piles, which is called a pile breakwater in this chapter. The closely spaced piles induce energy dissipation due to viscous eddies formed by the flow through the gaps. To examine the wave scattering by vertical piles, hydraulic model tests have been used. Efforts toward developing analytical models to calculate the reflection and transmission coefficients have also been made. Recently, Suh et introduced a curtain-wall-pile breakwater, the upper part of which is a ciu tain waU and the lower part consisting of an array of vertical piles. They developed a mathematical model that predicts various hydrodjmamic characteristics of a cmtain-wall-pile breakwater. More recently, Suh and Ji extended the model to a multiple-row breakwater. 

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