Combined Supercharging System: The Best Fit for Submarine Engines

2001 ◽  
Author(s):  
R. Herrmann
Keyword(s):  
Test Bench ◽  
Specific Power ◽  
Two Stage ◽  
Pressure Stage ◽  
Classical Systems ◽  
Two Systems ◽  
High Pressure Stage ◽  
Low Sensitivity ◽  
Best Fit ◽  
New System

Abstract The two types of supercharging processes, either with turbocharger or with mechanically driven compressor are the two systems known to be used on diesel engines for submarines. Each of these two systems has its own limitations. A two stage supercharging system has been investigated and developed by S.E.M.T. Pielstick. This system is based on a turbocharger used as a low-pressure stage combined with a high-pressure stage compressor which is mechanically driven by the engine. Test bench results are compared with those obtained with the classical systems. The new system with two-stage compression has an advantage particularly for the following main points: - specific power, - air and fuel specific consumptions, - capability to sustain high exhaust back pressures as well as low suction pressures and low sensitivity to their fluctuations, - safety against engine stalling in case of loss of submersion control.

scholarly journals Analysis and Improvement of a Two-Stage Centrifugal Compressor Used in an MW-Level Gas Turbine

2018 ◽  
Vol 8 (8) ◽  
pp. 1347 ◽  
Author(s):  
Wei Zhu ◽  
Xiao-Dong Ren ◽  
Xue-Song Li ◽  
Chun-Wei Gu
Keyword(s):  
High Pressure ◽  
Gas Turbine ◽  
Centrifugal Compressor ◽  
Pressure Ratio ◽  
Low Pressure ◽  
Two Stage ◽  
Vaned Diffuser ◽  
Pressure Stage ◽  
Optimization System ◽  
High Pressure Stage

The performance of a low/high-pressure-stage centrifugal compressor in a land-use MW-level gas turbine with a pressure ratio of approximately 11 is analyzed and optimized with a 1D aerodynamic design and modeling optimization system. 1D optimization results indicate that the diameter ratio of the low-pressure-stage centrifugal compressor with a vane-less diffuser, and the divergent angle of the high-pressure-stage centrifugal compressor with a vaned diffuser, are extremely large and result in low efficiency. Through modeling design and optimization system analysis, a tandem vaned diffuser is used in the low-pressure stage, and a tandem vaned diffuser with splitter vanes is adopted in the high-pressure stage. Computational fluid dynamics (CFD) results show that the pressure ratio and efficiency of the optimized low/high-pressure-stage centrifugal compressor are significantly improved. Coupling calculations of the low/high-pressure stage of the original and optimized designs are conducted based on the results of MW-level gas turbine cycles. CFD results show that the pressure ratio and efficiency of the optimized two-stage centrifugal compressor increase by approximately 8% and 4%, respectively, under three typical load conditions of 100%, 90%, and 60%.

The Rise of Academic Innovationism

2018 ◽  
pp. 79-115
Author(s):  
Steven Brint
Keyword(s):  
Research Universities ◽  
Knowledge Exchange ◽  
Reciprocal Relations ◽  
Academic Innovation ◽  
The Future ◽  
Two Systems ◽  
Research And Education ◽  
New System

This chapter discusses the analytical contrast between the two systems for organizing research and education, the system of academic professionalism and the system of academic innovationism. Under the impetus of academic innovationism, universities became more porous to the outside world and reciprocal relations of knowledge exchange grew denser. On balance, the new system contributed significantly and positively to the research prowess of universities. But it has also yielded a spotty record—some extraordinary successes but also many short-lived, troubled collaborations. Some universities invested heavily in the infrastructure to foster academic innovation and had little to show for their investments. For research universities, the challenge for the future will be to expand the possibilities to contribute more to the national innovation effort.

A simple relationship between Buchholz's new system of ordinal notations and Takeuti's system of ordinal diagrams

1987 ◽  
Vol 52 (3) ◽  
pp. 577-581 ◽  
Author(s):  
Mitsuhiro Okada
Keyword(s):  
Original System ◽  
Simple Relationship ◽  
Ordered Sets ◽  
Two Systems ◽  
Ordinal Notations ◽  
New System

Buchholz [4] simplified the system of ordinal notations of the Schütte school (cf. [12]), by using the notion of collapsing functions (cf. [5]). In this paper we give a simple relationship between Buchholz's new system of ordinal notations and Takeuti's system of ordinal diagrams. From this simple relationship it turns out that the structures of these two systems are very close.We give two systems OT(I) (§1) and OT(I, A) (§2) of ordinal notations which are considered generalizations of Buchholz's original system, where I and A are well-ordered sets. The original system OT of Buchholz [4] is OT(ω + 1, {0}) in our sense. Here the set OT(I) of ordinal notations is defined as a subset of the set Od(I) of ordinal diagrams in [6], and the set OT(I, A) of ordinal notations as a subset of the set O(I, A) of ordinal diagrams in [14].

Experiment Study on Performances of Servo Pump Used in Hydraulic Press Machine

2012 ◽  
Vol 516-517 ◽  
pp. 892-895 ◽  
Author(s):  
Jun Gao ◽  
Guo Yi Yan ◽  
Gen Yun Peng ◽  
Guan Nan Xi
Keyword(s):  
Energy Efficiency ◽  
Control System ◽  
Working Conditions ◽  
Hydraulic System ◽  
Test Bench ◽  
Hydraulic Press ◽  
Experiment Study ◽  
Two Systems ◽  
Positive Meaning ◽  
Valve Control

As we known, the energy efficiency of pump-control system is higher than valve-control system. So, using pump-control system to replace valve-control system has a positive meaning to improve the energy efficiency in hydraulic press machine. In order to research the performance of servo pump used in hydraulic press machines, the present study is conducted. First, a test bench for comparison of pump-control and valve-control system is established. In this test bench, the pump of former valve-control system and the servo pump are settled. These two pumps are switched by solenoid to supply oil for the hydraulic system. Then, host PC, target PC, I/O board and other hard-wares are connected. Soft-wares and the corresponding driver board are applied to collect data. In order to test the performances of the pressure, velocity and displacement under the condition of the valve-control system and pump-control system, the two systems are tested with the same working conditions. The performance of repeatability and energy efficiency are also obtained. The results show that it’s feasible to apply servo pump to hydraulic press machine. And under the pump-control condition, the velocity and pressure performance of press machine is more stable.

scholarly journals Studies in Qur’an and Hadith

1989 ◽  
Vol 6 (2) ◽  
pp. 329-335
Author(s):  
Muhammad Khalid Mas’ud
Keyword(s):  
Islamic Law ◽  
Early Period ◽  
Doctoral Dissertation ◽  
Central Theme ◽  
Early Islam ◽  
Two Systems ◽  
The Subject ◽  
Original Reading ◽  
New System ◽  
Husband And Wife

David S. Powers’ book, originally a doctoral dissertation submitted toPrinceton University, is a welcome addition to the already growing corpusof studies revising Joseph Schacht’s thesis that Islamic law did not exist duringthe lifetime of the Prophet. This is, however, not the central theme ofthe book. Powers contends that the Islamic law of inheritance is not identicalto the system of inheritance revealed to Prophet Muhammad and that theMuslim community is not in possession of the original reading and understandingof several Qur’anic verses and Prophetic hadith.The thesis presented in this book can be summarized as follows:Islamic law began to develop with Qur‘anic legislation which was moreclear and systematic on the subject of inheritance. In pre-Islamic Arabia theintergenemtional transmission of property was by seniority rather than by directdescent. The Qur’an introduced a new system of inheritance which reflecteda transition from tribalism to individualism, with more emphasis on the rightsof women to property. The author sees two systems of the law of inheritancein Islam:1) The proto-Islamic law of inheritance which existed only during2) Islamic law of inheritance, which exists as ‘ilm al-farii‘id.the lifetime of the Prophet; and,Powers contends that the proto-Islamic system was mainly testatory andthe property was distributed according to fixed shares only in the absenceof a will. Husband and wife, not being blood relatives, inherited as testatoryheirs.The author divides his dissertation into two parts. In the first part he dealswith the proto-Islamic, in the second with the Islamic system of inheritance.The first part proceeds by looking at the practice of bequest and testation inMakkah and Madinah in early Islam, giving special attention to the inheritancebetween husbands and wives, and the Qur’anic law of testation and intestacy.The second part proceeds by looking at socio-economic developmentsin the early period and contends that people in power manipulated the Qur‘anic ...

scholarly journals Prospects of using a liquid ring vacuum pump with automatic adjustable discharge window when grinding grape seeds and pomace

2021 ◽  
pp. 55-60
Author(s):  
Юрий Юрьевич Родионов ◽  
Анастасия Игоревна Скоморохова ◽  
Юрий Викторович Родионов ◽  
Дмитрий Вячеславович Никитин ◽  
Сергей Иванович Данилин ◽  
...  
Keyword(s):  
Vacuum Pump ◽  
Grape Pomace ◽  
Biologically Active ◽  
Specific Power ◽  
Industrial Complex ◽  
Grape Seeds ◽  
Two Stage ◽  
Plant Products ◽  
Plant Powders ◽  
Liquid Ring

Для повышения сохранения биологически активных веществ, уменьшения энергопотребления в процессе измельчения и получения порошка заданной степени помола из виноградных выжимок и семян предлагается использование установки двухступенчатой дисково-шаровой вакуумной мельницы. Предложенная конструкция двухступенчатой мельницы оказывает влияние на безопасность работы (исключаются взрывы) и экологичность (не создает запыленности окружающей среды). В конструкции разработанной установки важным объектом является вакуумный насос. Приведены устройство и основные принципы работы классического одноступенчатого водокольцевого вакуумного насоса производства ОАО «БЕСКОМ» и жидкостно-кольцевого вакуумного насоса с возможностью автоматического регулирования размеров нагнетательного окна, разработанного в ФГБОУ ВО «ТГТУ» на кафедре «МИГ». Показаны основные преимущества предлагаемого насоса по сравнению с классическим вариантом. На основе испытаний был проведен сравнительный анализ разработанного жидкостно-кольцевого вакуумного насоса с автоматическим регулируемым размером нагнетательного окна и классического вакуумного насоса равной быстроты действия, результаты которого продемонстрировали существенную эффективность использования первой машины. Установлено, что затраты удельной мощности в процессе транспортирования растительных порошков на 20-25% ниже при равной быстроте действия. Экономический расчет демонстрирует эффективность применения новой конструкции разработанного вакуумного насоса в технологическом процессе тонкого измельчения сухих растительных продуктов за счет вакуумного отвода заданной фракции помола. Поэтому разработанный насос рекомендуется использовать для измельчения сухих сыпучих растительных продуктов на крупных перерабатывающих предприятиях агропромышленного комплекса, пищевой, фармацевтической и парфюмерной отраслях промышленности. To increase the preservation of biologically active substances, reduce energy consumption in the grinding process and obtain a powder of a given degree of grinding from grape pomace and seeds, it is proposed to use a two-stage disk-ball vacuum mill. The proposed design of a two-stage mill affects the safety of work (excluding explosions) and environmental friendliness (does not create a dusty environment). An important object in the design of the developed installation is the vacuum pump. The device and basic principles of operation of a classic single-stage liquid ring vacuum pump manufactured by JSC "BESCOM" and a liquid ring vacuum pump with the ability to automatically adjust the size of the discharge window, developed at the TSTU Department of MIG are presented. The main advantages of the proposed pump in comparison with the classic version are shown.Based on the tests, a comparative analysis of the developed liquid ring vacuum pump with an automatically adjustable discharge window size and a classical vacuum pump of equal action speed was carried out, the results of which demonstrated the significant efficiency of using the first machine. It has been established that the specific power consumption in the process of transporting plant powders is 20-25% lower with the same speed of action. An economic calculation demonstrates the effectiveness of using a new design of the developed vacuum pump in the technological process of fine grinding of dry plant products due to the vacuum removal of a given grinding fraction. Therefore, the developed pump is recommended to be used for grinding dry bulk plant products at large processing enterprises of the agro-industrial complex, food, pharmaceutical and perfumery industries.

scholarly journals Physiological and Notational Comparison of New and Old Scoring Systems of Singles Matches in Men's Badminton

2011 ◽  
Vol 17 (1) ◽  
pp. 6-17 ◽  
Author(s):  
Hsin Lian CHEN ◽  
Chang Jun WU ◽  
Trevor C. CHEN
Keyword(s):  
Perceived Exertion ◽  
Physiological Responses ◽  
Scoring Systems ◽  
Physiological Data ◽  
Systematic Observation ◽  
Time Frequency ◽  
Two Systems ◽  
Playing Time ◽  
Lactate Levels ◽  
New System

LANGUAGE NOTE | Document text in English; abstract also in Chinese. This study compared the physiological responses and shot selection preferences of male singles players between thenew (rally-point) and old (scoring-by-service) scoring systems. Ten male athletes each played two matches against the same opponent on different days using the lottery method. Matches were notated using a systematic observation instrument, and physiological data were measured using heart rate (HR), ratings of perceived exertion (RPE) and blood lactate levels (LA). Results showed no differences in peak HR, RPE or LA responses between the two systems. However, players spent more time at an HR greater than 90%HRpeak under the old system (63%) than under the new system (54%). Notational analysis demonstrated a significant decrease in total match playing time (PT: 29 min), work time (10 min), work density (0.57), rest time (18 min), effective playing time (36%), number of rallies (203) and serves (35) under the new system as compared to the old system (e.g. PT: 42 min). No significant differences were noted between the two systems for number of shots, rally time, stroke time, frequency distribution of shot selection and positions during the matches, and for shot methods on the last shot of each rally. These findings suggest that the new system can significantly shorten PT compared to the old system, and that physiological responses, shot selection and positions do not affect between the systems. Meanwhile, the greater proportion of time spent at higher HR intensities under the old system may be attributed to the longer playing time with the opponent. 本研究目的，針對「新(落地得分)、舊制(發球得分)羽球單打比賽時之生理反應和擊球方式」做比較。以羽球正式比賽抽籤方式讓10位大學男子甲組羽球選手，決定其各二場新、舊制羽球單打比賽同一位對手之方式。以高速攝影機拍攝每場比賽做為系統性觀察法之內容分析，並在每場比賽時測驗心跳率 (HR)、運動自覺量表(RPE)和血乳酸濃度 (LA)做為生理反應的評估指標。結果顯示，羽球新、舊制比賽間引起心跳率峰值 (HRpeak)、RPE或血乳酸上升的反應並無統計差異。然而，舊制比賽時>90%HRpeak強度的比率(63%)明顯比新制 (54%)來得多。新制比賽的整場比賽完成時間 (PT：29分鐘)、淨比賽時間 (10分鐘)、運動密度 (0.57)、休息時間 (18分鐘)、比賽時間效益 (36%)、每球來回完成次數 (203)及發球次數 (35)都明顯比舊制 (例 如PT：42分鐘)縮短，但二種不同比賽間在揮拍次數、每球來回完成時間、擊球時間、擊球方式、擊球位置及每球最後一拍的擊球方式均無統計差異。這些結果顯示，新賽制規則改變會比舊賽制明顯縮短比賽時間，但不同賽制間所引起的生理反應、擊球方式及位置則不因規則改變而受到影響。此外，舊賽制比新賽制出現較高心跳率分佈情形，可歸因於舊制比賽之雙方選手有較多對抗機會或較長比賽時間所造成的。

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