High Pressure Part Research Articles

Design and Performance of a High-Pressure Ratio Turbocharger Compressor Part 1: Design Considerations

The compressor design requirement was for a pressure ratio of 3.6, with a peak pressure ratio of 4.3 at the maximum non-dimensional speed of the impeller of 1.66. Due to the stress-limited speed, an aluminium alloy impeller was specified, the impeller discharge blade backsweep had to be restricted and the application of prewhirl was considered from the outset as a means of extending the operating range. A non-dimensional conceptual design procedure, including the effect of inlet prewhirl, was applied to the design of three turbo- charger impellers. An impeller, designated A, was designed with the inclusion of 25° of prewhirl. A second impeller, designated B, was designed with zero prewhirl for comparison purposes, but was not manufactured. A third impeller, C, was manufactured through the modification of an existing design and the design study was applied to the assessment of this third design.

Design and Performance of a High-Pressure Ratio Turbocharger Compressor Part 2: Experimental Performance

The performance of two turbocharger impeller designs was evaluated experimentally. The compressor design requirement was for a pressure ratio of 3.6, with a peak pressure ratio of 4.3 at a maximum non-dimensional impeller speed of 1.66. Due to the stress-limited speed the impeller discharge blade backsweep had to be restricted and the application of prewhirl was considered from the outset as a means of extending the operating range. An impeller, designated A, was designed with 25° of prewhirl applied. A second impeller, designated B, was designed with zero prewhirl for comparison purposes, but was not manufactured. A third impeller, C, was manufactured, in place of impleller B, through the modification of an existing design. This experimental study includes the assessment of this third impeller together with impeller A.

A deep section of accretionary complex: Susunai Complex in Sakhalin Island, Northwest Pacific Margin

Abstract A deep section of accretionary complex, the metamorphosed Susunai Complex, is observed on Sakhalin Is., Russia. High pressure part of pumpellyite‐actinolite facies metavolcanics, metacherts and metapelites are well exposed and constitute a tectonic pile preserving primary structures related to underplating of the oceanic crust. Three stages of deformation, D1 through D3, suggest successive deformation during subduction, underplating and exhumation of the complex. Oceanic material in the complex is more abundant than other well documented ancient accretionary complexes (e.g. the Shimanto Belt in southwest Japan and the Ghost Rocks Formation in Alaska), which were shallowly underplated. At Susunai, deep down‐stepping of a décollément has scraped off the upper part of the oceanic crust, primarily the pillowed basalt horizon. This down‐stepping results from crustal weakening as overpressured water is released from the fractured oceanic crust during metamorphism.

Precision Cleaning in a Production Environment with High-Pressure Water

The increasing contamination control requirements for disk drives, and the prevailing mandate to climinate chlorinated solvents in cleaning applications have allowed high-pressure water spray to emerge as an effective and environmentally sound method for cleaning. Certain substrates, such as machined metals and alloys, can be cleaned using high-pressure water to state-of-the-art cleanliness levels. Following developmental investigations in the laboratory, two cleaners utilizing high-pressure (up to 3000 psig), high-flow (up to 50 gpm) water have been procured for use at suppliers of critical disk-drive components. Acceptance-runoff, certification, and production-run cleanliness data pertaining two the two high-pressure cleaners are presented here in terms of liquid-born particle counts on contaminants extracted from substrates ultrasonically, or by means of a low-pressure water spray. Results indicate that residual particulate contamination levels on high-pressure sprayed parts may be lower by more than two orders of magnitude compared with those obtained by more conventional cleaning methods. The cleaning efficiency increases significantly with particle size. The importance of nozzle manifold design and placement, for both cleaning and drying, is demonstrated quantitatively with examples of the deleterious consequences of not optimizing them. The underlying cleaning mechanism is explained briefly. Potential advantages and disadvantages associated with high-pressure water spray cleaning are fully discussed, and recommendations are offered for utilizing this technology most effectively.

Nucleation Phenomena in Flowing High-Pressure Steam Part 2: Theoretical Analysis

The paper is the second of a set and gives the theoretical part of an investigation into limiting supersaturation inflowing high-pressure steam. The treatment is one dimensional but includes refinements gradually developed in earlier studies; the complete final version is presented in summary form. Applications are to the authors' own experimental results and others available in the literature and the agreement with the measured pressure distributions is very good. The quality of agreement with the few measured droplet sizes is less good, the theory generally underestimating the observed mean droplet diameters. The summaries presented give variations of limiting supersaturation and resulting droplet sizes with the Wilson point pressure and the rate of expansion.

Cavitation indices for high pressure orifice plate energy dissipators

A problem of providing a simple device for pressure dissipation in mine underground high pressure water reticulation systems was investigated; a required feature of this device was operation without cavitation. An orifice plate was selected, and various orifice diameter ratios (0.206–0.444) for a range of upstream pressures (2000–7000 kPa) were examined for their incipient cavitation points and flow/pressure drop behaviour. Experimental work was conducted in two parts, low pressure and high pressure; the low pressure part of the work was carried out at the University of the Witwatersrand and the high pressure part at the East Driefontein Gold Mine. Both sets of experiments yielded data that were inconsistent with previously predicted values of incipient cavitation under conditions of relatively low head (up to 137 m of water); analysis of the results yielded a new simple cavitation prediction method based on cavitation inception and orifice pressure drop data which is easily presented in graphical form. The results showed that upstream pressure affected the pressure drop required for incipient cavitation, for the same orifice size; and that the orifice ratio affected the pressure drop required for incipient cavitation, for the same upstream pressure.

高圧下における溶接金属の窒素吸収 ＩＩ 高圧溶接ふん囲気におけるステンレス鋼溶接金属の窒素吸収

高圧下における溶接金属の窒素吸収 ＩＩ 高圧溶接ふん囲気におけるステンレス鋼溶接金属の窒素吸収

II. Transmission of reaction products through a nozzle-skimmer system

In order to connect the high pressure part of a fission fragment separator to the low pressure one, a nozzle-skimmer system is used. We have studied the properties of this apparatus, simulating the reaction products by clusters created in an aerosol generator. The main feature of such a device consists in its ability to give lower downstream pressure while passing most of high mass fragments. These two characteristics are examined both from an experimental and a theoretical point of view. In particular we give some simple expressions to calculate the gas and cluster jet shape as a function of the distance from the nozzle from which one can derive the gas and cluster flux through a skimmer.

An Experimental Determination of the Solidification Velocity for Mineral Oils

The behavior of mineral oils under high hydrostatic pressures is studied. It is found that a test oil converts from a liquid to a solid faster than within 9 μs when the time mean value of the pressure is 1,200 N/mm2 (— 12,000 atmospheres). As the solidification velocity for liquids increases approximately proportional to the pressure rise above the static solidification pressure, this solidification time shows that rolling element bearings under normal working conditions have solidified oil in the high pressure part of the contact.

THEORETICAL STUDY ON THE EFFECT OF PRESSURE DEPENDENCY OF WALL ELASTICITY UPON THE ARTERIAL PRESSURE PATTERN

The effect of the pressure dependency of the arterial wall elasticity upon the arterial pressure form was treated theoretically in this paper. First, the variation of rectangular pressure pattern was treated by introducing new wave equations. The arterial pressure pattern was then calculated, using an approximation of the wave form by a number of square patterns of the same duration. Because the elasticity of the arteries increases with blood pressure, the high pressure part of the systolic peak advances farther ahead of the preceding lower part as the wave propagates. As a result of calculation the variation of the pressure pattern showed a good agreement with the experimental data.

A demonstration heat pump

Thermometers were put in the refrigerant line at the four obvious points and two pressure gauges were added in the high and low pressure parts of the system.

Distensibility of digital blood vessels in cold environment.

To determine finger-tip vascular distensibility when all of the vessels are subjected to a uniform pressure, an appropriate plethysmograph is used to follow the increase after local venous occlusion. When the finger shows no further systematic increase in volume (volume B), an arterial occlusion is applied to the upper part of the arm. Blood will then flow from the high pressure parts of the vascular bed of the finger tip until the pressure level is related to the venous occlusion cuff pressure to give a new volume (C). Release of the venous occlusion cuff permits all of the blood vessels in the finger tip to come into equilibrium with the pressures in the vessels of the arm to give a measure of the volume (D) contained at the low pressure. The difference between volumes C and D represents the distention of the entire vascular bed of the finger tip for the pressure difference between the occlusion and the final static pressure level. When subjects are exposed to a cold environment, distensibility of the finger-tip vessels decreases, with evidence for involvement of both high- and low-pressure vessels. Submitted on September 19, 1960

High Pressure Turbine Practice

IMPORTANT developments are taking place in the large power stations of electric supply companies. In the Electrical Times of September 19 there is an interesting account of the Loeffler boilers, which will supply steam turbines at the enormous pressure of 2,000 pounds per square inch. The exhaust steam from the high-pressure turbine is at a pressure of about 195 pounds per sq. in. and is reheated by steam from the boilers before passing into the low-pressure turbine. The North Metropolitan Supply Co. has two stations at Brimsdown called A and B. In the old station A the conditions were unfavourable to economical generation as the turbine pressure was only 150 lb. per sq. in. Owing to the favourable economic possibilities offered by the Loeffler boiler the station is being altered; two boilers each having a capacity of 210,000 lb. per hour, each operating at a pressure of 2,000 lb. per sq. in. and at a total temperature of 940° F., have been ordered from the Mitchell Engineering Co., Ltd., which has acquired the British rights from the well-known firm of Vitcovice. If petrol drops on the steam pipes at these high temperatures it bursts into flame. About twenty of these boilers are used abroad in Czechoslovakia, Germany and Russia. To get the best results it was necessary to have a set of 50,000 kilowatts. As a machine of this size could not be fitted into Brimsdown A it was divided into two. The high-pressure part has a power of 20,000 kw. and the low-pressure part has a power of 30,000 kw. It is claimed that certain advantages will accrue from running the machines in series.