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This report documents an investigation into the feasibility of applying wear debris analysis methods as a maintenance tool for aircraft hydraulic systems. A breadboard was designed and operated, fluid samples were analyzed and trended. No relevant failures were experienced and limited conclusions reached. Recommendations are made for further investigations. (Author)

This report documents findings on the non-operating reliability of accumulators. The study consists of over 326 million part hours. The sources show an overall storage failure rate of 32.6 FITS (failures per billion hours) with a one sided 90% confidence limit of 54.8 FITS for hydraulic accumulators. Elements of accumulator design are discussed. This information is part of a research program being conducted by the U.S. Army Missile Command, Redstone Arsenal, Alabama. The objective of this program is the development of non- operating (storage) reliability prediction and assurance techniques for missile materiel.

This report describes the continued development and test verification of digital computer models used to simulate hydraulic systems under dynamic conditions. Frequency and transient models of a variable delivery vane pump and a fixed displacement piston-type hydraulic motor are included. Additional verification and development of the transient model for the piston-type hydraulic pump was accomplished. Verification and development of a computer program to describe the mechanical response of a hydraulic line to internal excitations from a hydraulic pump was begun. This effort was a continuation of the basic contract wherein four computer programs for hydraulic system dynamic analysis were developed.

This study analyzed the life cycle costs, cost of fires, and benefits of using a new nonflammable hydraulic fluid (CTFE) in future tactical aircraft versus a fire retardant fluid (Mil-H-83282) currently used in tactical aircraft. The study assumed that future hydraulic systems will use 8000 psi pressure. An analogy was made using a McDonnell Douglas Corporation study as the basis. This study compared Mil-H-83282 and CTFE at 8000 psi showing weight as the primary difference. Therefore, this weight difference, the fluid price difference, and the fuel consumption of an F-15 were used to determine the life cycle cost difference between the two systems. Since the added weight was slight, only the additional fuel consumption to fly the extra weight was significant. The added life cycle costs for using CTFE was estimated at $11.4 million in FY87 dollars. Since CTFE will prevent hydraulic fires, an estimate of Mil-H-83282 fire costs was attempted. The differences in the benefits were primarily in the survivability and capability of the aircraft. Taking these differences together CTFE is slightly better than Mil-H-83282 in peacetime. This difference becomes more pronounced in wartime. Finally, a sensitivity analysis was conducted on the assumptions. Based on these analyses, a conclusion was made that CTFE was a viable alternative at 8000 psi. However, further research is needed on the logistical problems related to the new pressure and fluid. Also, further study is needed on the effectiveness of Mil-H-83282 against the causes of hydraulic fires.

Major developments are examined which have taken place to date in the analysis of the power and energy demands on the APU/Hydraulic/Actuator Subsystem for space shuttle during the entry-to-touchdown (not including rollout) flight regime. These developments are given in the form of two subroutines which were written for use with the Space Shuttle Functional Simulator. The first subroutine calculates the power and energy demand on each of the three hydraulic systems due to control surface (inboard/outboard elevons, rudder, speedbrake, and body flap) activity. The second subroutine incorporates the R. I. priority rate limiting logic which limits control surface deflection rates as a function of the number of failed hydraulic. Typical results of this analysis are included, and listings of the subroutines are presented in appendicies.

The Hydraulic Transient Thermal Analysis (HYTTHA) computer program has been developed to predict temperatures, and temperature gradients in hydraulic components and systems, due to changes in flow demands. The steady state flows and pressures throughout the system are used by the thermal portion of the program to predict fluid temperatures, line wall temperatures, component temperatures, and other component variables. The engineering input data to the program is normally available to a design engineer. Additional components, not covered here, may be added if necessary without much effort.

This report describes the development and verification of four computer programs used to simulate hydraulic systems under dynamic conditions. The programs were developed by McDonnell Douglas Corp. under contract with the Air Force. The Hydraulic Systems Frequency Response (HSFR) program predicts the ripple in the flow from piston-type pumps and shows how it is transmitted and attenuated through the system. It predicts the resonant frequencies and the locations and amplitudes of the standing waves of the oscillatory flow and pressure. The Steady-State Flow Analysis (SSFAN) program defines the system flow and pressure distribution resulting from the simultaneous operation of actuator devices under any combinations of loads and rates. The Hydraulic Transient Analysis (HYTRAN) program simulates the dynamic response of a system to sudden changes in load flow demand. The typical input to the system is a valve motion from which pressure and flow disturbances propagate through the system, causing pump and component responses. The Hydraulic Transient Thermal Analysis (HYTTHA) program predicts the effects of system heat generation and dissipation of the temperatures and performance of a hydraulic system.

SSFAN is a steady state hydraulic flow and pressure analysis computer program. Its primary purpose is to analyze non-linear resistance aircraft hydraulic systems. The program handles complex flow networks containing flow and/or pressure discontinuities such as unbalanced area actuators and check valves. Solutions for a combination of simultaneously operating subsystems are easily obtained. The program is designed using a building block approach so that new component or element models may be added with minimum change to the main program. The solution method is a Matrix type, using iteration to obtain a final flow and pressure balance. The program internally corrects viscosities for pressure, determines whether flow is laminar, transition or turbulent for use of appropriate resistance factors and corrects reservoir pressure for altitude effects. The program was written with the aircraft hydraulic system designer in mind. The terminology and units are commonly used terms such as fluid viscosity in centistokes, temperatures in degrees Fahrenheit and flow in gallons per minute. Conversion of units for calculation is accomplished internally in the program. (Author)

The component data handbook has been developed to aid users of the aircraft hydraulic system dynamic analysis computer programs HSFR, SSFAN, and HYTRAN in selecting input data. The handbook provides brief descriptions of the general usage components modeled by these computer programs, tabulates the necessary input data for each program and catalogs typical data trends or actual input data of components that have been simulated.

The hydraulic transient analysis (HYTRAN) computer program has been developed to simulate the response of a hydraulic system to sudden changes in flow demand by the system loads. For selected component temperatures, pump RPM, and initial steady state conditions, the program will calculate the pressures and flow amplitudes resulting from changes in flow demand or some other controller input. It will predict transient pressures due to waterhammer and the onset of cavitation due to the opening and closing of valves. The engineering input data to the program is normally available to a design engineer. When specialized components are required that are not covered by existing subroutines, these may be simulated by adding to the program.

This report documents findings on the non-operating reliability of hydraulic and pneumatic actuators. Long term non-operating data has been analyzed and storage failure rate predictions have been made. This report is a result of a program whose objective is the development of non-operating (storage) reliability prediction and assurance techniques for missile materiel. The analysis results will be used by U. S. Army personnel and contractors in evaluating current missile programs and in the design of future missile systems.

Study on the Application of Temperature Difference in the Evaluation of Pipe Break Size in Recirculation Systems Based on Thermal-hydraulic Model Analysis 作者： Hwang, Mr. Sheng-Dih 1 作者单位： 1. National Atomic Research Institute 通讯作者： Hwang, Mr. Sheng-Dih Email:[email protected] 提交时间： 2025-02-20 13:31:54 摘要: This study investigates the temperature difference between recirculation loops following an instantaneous pipeline rupture. The analysis shows that the pipe rupture leads to the conversion of energy in an open system, resulting in the coolant escaping from the broken exhibiting a lower temperature compared to the intact loop. A theoretical model based on energy balance principles effectively explains these temperature differences. Validation through the Modular Accident Analysis Program (MAAP5) simulations and training simulator results confirms that both tools accurately predict temperature changes during station blackout and loss of coolant accident scenarios. This study examines the effects of coolant pipe ruptures on the recirculation system and compares the resulting trends with the simulator data. The model can serve as a foundation for future quantitative research, enabling a deeper understanding of the recirculation system during a break transient period. The use of computer simulation codes will ensure the main phenomena, improve accident management strategies, and establish a basis for future quantitative analyses. And, the results of this study also indicate that the correlation between the temperature difference between pipelines and the break size of pipelines is more strongly assisted by the peak cladding temperature. Loss of Coolant Accident (LOCA) temperature difference break size MAAP5 piping cooling loop 来自： Hwang, Mr. Sheng-Dih 分类： 物理学 >> 核物理学 备注: 已向《Nuclear Science and Techniques》投稿 引用： ChinaXiv:202502.00170 (或此版本 ChinaXiv:202502.00170V1 ) DOI:10.12074/202502.00170 CSTR:32003.36.ChinaXiv.202502.00170 科创链TXID： 19ee7f8b-b0d2-4ff2-b524-e9a5af983a43 推荐引用方式： Hwang, Mr. Sheng-Dih.Study on the Application of Temperature Difference in the Evaluation of Pipe Break Size in Recirculation Systems Based on Thermal-hydraulic Model Analysis.中国科学院科技论文预发布平台.[DOI:10.12074/202502.00170] 版本历史 [V1] 2025-02-20 13:31:54 ChinaXiv:202502.00170V1 下载全文

SSFAN is a steady state hydraulic flow and pressure analysis computer program. Its primary purpose is to analyze non-linear resistance aircraft hydraulic systems. The program handles complex flow networks containing flow and/or pressure discontinuities such as unbalanced area actuators and check valves. Solutions for a combination of simultaneously operating subsystems are easily obtained. The program is designed using a building block approach so that new component or element models may be added with minimum change to the main program. The solution method is a Matrix type, using iteration to obtain a final flow and pressure balance. The program internally corrects viscosities for pressure, determines whether flow is laminar, transition or turbulent for use of appropriate resistance factors and corrects reservoir pressure for altitude effects. A Quasi-transient section has been added to allow multiple steady state calculations when simulating subsystem operations. The data is stored and can be printed in either tabular form or computer plot form. The program was written with the aircraft hydraulic system designer in mind. The terminology and units are commonly used terms such as fluid viscosity in centistokes, temperatures in degrees Fahrenheit and flow in gallons per minute. Conversion of units for calculation is accomplished internally in the program. (Author)

SSFAN is a steady state hydraulic flow and pressure analysis computer program. Its primary purpose is to analyze non-linear resistance aircraft hydraulic systems. The program handles complex flow networks containing flow and/or pressure discontinuities such as unbalanced area actuators and check valves. Solutions for a combination of simultaneously operating subsystems are easily obtained. The program is designed using a building block approach so that new component or element models may be added with minimum change to the main program. The solution method is a Matrix type, using iteration to obtain a final flow and pressure balance. The program internally corrects viscosities for pressure, determines whether flow is laminar, transition or turbulent for use of appropriate resistance factors and corrects reservoir pressure for altitude effects. A Quasi-transient section has been added to allow multiple steady state calculations when simulating subsystem operations. The data is stored and can be printed in either tabular form or computer plot form. The program was written with the aircraft hydraulic system designer in mind. The terminology and units are commonly used terms such as fluid viscosity in centistokes, temperatures in degrees Fahrenheit and flow in gallons per minute. Conversion of units for calculation is accomplished internally in the program. (Author)

Hydraulic fluid analysis for reducing wear, and detection of component failure

This report contains the results of a hazards analysis of the steam and hydraulic systems at the Western Area Demilitarization Facility (WADF) at Hawthorne, Nevada. The analyses have been divided into five plant areas: (1) Washout/Steamout Building North Tower; (2) Washout/Steamout Building South Tower; (3) Refining Building; (4) Bulk Explosives Disposal Facility; and (5) Process Water Treatment Plant. The methodology used was a combination of failure modes and effects analysis (FMEA) and fault tree analysis (FTA), with quantification accomplished through the use of a fault tree computer model.

This report contains the results of a hazards analysis of the steam and hydraulic systems at the Western Area Demilitarization Facility (WADF) at Hawthorne, Nevada. The analyses have been divided into five plant areas: (1) Washout/Steamout Building North Tower; (2) Washout/Steamout Building South Tower; (3) Refining Building; (4) Bulk Explosives Disposal Facility; and (5) Process Water Treatment Plant. The methodology used was a combination of failure modes and effects analysis (FMEA) and fault tree analysis (FTA), with quantification accomplished through the use of a fault tree computer model.