Large-Scale Advanced Prop-Fan (LAP) pitch change actuator and control design report

In recent years, considerable attention has been directed toward improving aircraft fuel consumption. Studies have shown that the high inherent efficiency previously demonstrated by low speed turboprop propulsion systems may now be extended to today's higher speed aircraft if advanced high-speed propeller blades having thin airfoils and aerodynamic sweep are utilized. Hamilton Standard has designed a 9-foot diameter single-rotation Large-Scale Advanced Prop-Fan (LAP) which will be tested on a static test stand, in a high speed wind tunnel and on a research aircraft. The major objective of this testing is to establish the structural integrity of large-scale Prop-Fans of advanced construction in addition to the evaluation of aerodynamic performance and aeroacoustic design. This report describes the operation, design features and actual hardware of the (LAP) Prop-Fan pitch control system. The pitch control system which controls blade angle and propeller speed consists of two separate assemblies. The first is the control unit which provides the hydraulic supply, speed governing and feather function for the system. The second unit is the hydro-mechanical pitch change actuator which directly changes blade angle (pitch) as scheduled by the control

Design and development of auxiliary components for a new two-stroke, stratified-charge, lean-burn gasoline engine

A unique stepped-piston engine was developed by a group of research engineers at Universiti Teknologi Malaysia (UTM), from 2003 to 2005. The development work undertaken by them engulfs design, prototyping and evaluation over a predetermined period of time which was iterative and challenging in nature. The main objective of the program is to demonstrate local R&D capabilities on small engine work that is able to produce mobile powerhouse of comparable output, having low-fuel consumption and acceptable emission than its crankcase counterpart of similar displacement. A two-stroke engine work was selected as it posses a number of technological challenges, increase in its thermal efficiency, which upon successful undertakings will be useful in assisting the group in future powertrain undertakings in UTM. In its carbureted version, the single-cylinder aircooled engine incorporates a three-port transfer system and a dedicated crankcase breather. These features will enable the prototype to have high induction efficiency and to behave very much a two-stroke engine but equipped with a four-stroke crankcase lubrication system. After a series of analytical work the engine was subjected to a series of laboratory trials. It was also tested on a small watercraft platform with promising indication of its flexibility of use as a prime mover in mobile platform. In an effort to further enhance its technology features, the researchers have also embarked on the development of an add-on auxiliary system. The system comprises of an engine control unit (ECU), a directinjector unit, a dedicated lubricant dispenser unit and an embedded common rail fuel unit. This support system was incorporated onto the engine to demonstrate the finer points of environmental-friendly and fuel economy features. The outcome of this complete package is described in the report, covering the methodology and the final characteristics of the mobile power plant

Rocketdyne LOX bearing tester program

The cause, or causes, for the Space Shuttle Main Engine ball wear were unknown, however, several mechanisms were suspected. Two testers were designed and built for operation in liquid oxygen to empirically gain insight into the problems and iterate solutions in a timely and cost efficient manner independent of engine testing. Schedules and test plans were developed that defined a test matrix consisting of parametric variations of loading, cooling or vapor margin, cage lubrication, material, and geometry studies. Initial test results indicated that the low pressure pump thrust bearing surface distress is a function of high axial load. Initial high pressure turbopump bearing tests produced the wear phenomenon observed in the turbopump and identified an inadequate vapor margin problem and a coolant flowrate sensitivity issue. These tests provided calibration data of analytical model predictions to give high confidence in the positive impact of future turbopump design modification for flight. Various modifications will be evaluated in these testers, since similar turbopump conditions can be produced and the benefit of the modification will be quantified in measured wear life comparisons

POGO Instabilities Suppression Evaluation

A dynamic (frequency response) analysis was made of a liquid oxygen feed system consisting of a low-speed inducer, a high-speed main pump and a positive displacement pulser utilized for simulating pogo induced pressure oscillations. Based on the results of the analysis, an active control system for suppression of pulser generated pressure oscillations was designed, fabricated and tested. The test results verified that the suppressor was effective in attenuating the generated pressure oscillations over the frequency range from 10 to 30 Hz

Enhancement of synthetic jets by means of an integrated valve-less pump Part II. Numerical and experimental studies

The paper studies the performance of the new fluid jet actuator based on the novel principle of the generation of fluid jet, which has been presented in [Z. Travnicek, A.I. Fedorchenko, A.-B. Wang, Enhancement of synthetic jets by means of an integrated valve-less fluid pump. Part I. Design of the actuator, Sens. Actuators A, 120 (2005) 232-240]. The fluid jet actuator consists of a synthetic jet actuator and a valve-less pump. The resulting periodical fluid jet is intrinsically non-zero-net-mass-flux, in contrast to the traditional synthetic jet. The numerical results have been compared with the laboratory experiments comprising phase-locked smoke visualization and time-mean velocity measurements. The results have confirmed the satisfactory performance of the actuator

Advanced expander test bed program

The Advanced Expander Test Bed (AETB) is a key element in NASA's Chemical Transfer Propulsion Program for development and demonstration of expander cycle oxygen/hydrogen engine technology component technology for the next space engine. The AETB will be used to validate the high-pressure expander cycle concept, investigate system interactions, and conduct investigations of advanced missions focused components and new health monitoring techniques. The split-expander cycle AETB will operate at combustion chamber pressures up to 1200 psia with propellant flow rates equivalent to 20,000 lbf vacuum thrust

Comparison of 0D and 3D Hydraulic Models for Axial Piston Pumps

Abstract In this the paper, a comparison between a 0D and a 3D model for the simulation of an axial piston pump is presented. The lumped parameter approach implements a detailed mathematical model developed in the Amesim® environment for the evaluation of the geometric features of the variable chambers. The commercial tool PumpLinx® has been used for the 3D computational fluid dynamics model. The aim is to assess the capability of the 0D model in predicting the main quantities and to evaluate the use of the three-dimensional analysis for fine tuning purposes. The comparison has been performed in conditions of fixed displacement and constant speed. A good agreement was found in the evaluation of the flow ripple and of the chamber pressure history

Team One Carbon Catcher Design Report

Overview The burning of fossil fuels largely contributes to the increase of CO2 in the atmosphere. The US Department of Transportation alone contributed almost 6 million metric tons of carbon dioxide emissions in 2018 (EIA). Due to this, this report proposes recycling captured CO2 into a base for cleaner burning fuel in order to reduce emissions from the transportation industry and many others, which has the potential to impact many areas. Extraction of atmospheric CO2 is possible through a membrane filtration system based on traditional nitrogen generation. The passive filtration system autonomously separates the CO2 from other air components, thereby reducing energy consumption. The system's working sensors and actuators utilize similar energy saving strategies, such as distributing cloud-computing services over multiple servers and mainframes to reduce computing power. The movement of air is directed by a scalable fan device, which is presented as a modular design to allow customization of fan parts to specific size and installation requirements. As an integrated device, Team 1’s Carbon Catcher operates with a high efficiency in order to maximize the commercial opportunity of converting captured CO2 into cleaner fuel while also reducing CO2 emissions and the greenhouse effect. Goal The goal of Team 1’s Carbon Catcher project proposal is to design a cost-effective, scalable, and modular atmospheric carbon dioxide removal system that is capable of being utilized in a range of urban environments and may fit a variety of different customer requirements or requests

The design and optimization of a condition monitoring device using data reduction techniques to estimate the leakage of a load sensing axial piston pump

Hydraulic systems are commonly used as solutions to industry challenges. Their excellent power-to-weight ratio can achieve specific design criteria that other power methods may not. In many hydraulic components, precision machining is present. This is to provide hydrodynamic lubrication between contacting components. By design, component life is greatly increased due to limited physical part interaction. Subsequently, any changes to the machined surfaces can result in accelerated and even catastrophic damage. Pressure compensated load sensing (PCLS) axial piston pumps are common in heavy duty hydraulic applications and provide flow in hydraulic systems. Typically, when a pump is exposed to common environmental contamination, internal machined surfaces can become damaged in the form of scoring. Depending on the degree of damage, this can result in increased leakage across lubricating boundaries or catastrophic failure due to adhesion. Component failure can then manifest in several ways. On a pump, slight wear can result in increased case drain leakage and the operator may not notice any performance issues, however, catastrophic failure may result in immediate system changes. A current method of evaluating the condition of an axial piston pump is by measuring the case drain leakage flow. This procedure involves installing a test flowmeter between the case drain leakage line and the reservoir and recording the flow at certain pressures. This can be an involved procedure and any time a closed hydraulic circuit is disassembled, the risk of introducing contamination is high. Additionally, robust, heavily used flowmeters can be inaccurate and unreliable due to wear and calibration errors. There is an obvious need to further develop the method of evaluating the health of a load sensing axial piston pump. The research contained in this thesis provides a potential cost effective alternative to case drain flow monitoring of PCLS axial piston pumps through the analysis of dynamic pump data. A nonlinear dynamic model of a load sensing axial piston pump and circuit is developed and validated with experimental dynamic pressure and swash angle position signals. The dynamic response of the pump outlet pressure, control piston pressure, and swashplate angle of a load sensing pump is shown to change with case drain leakage, both with the model and experimentally. iii A statistical procedure, Principal Component Analysis, (PCA), is applied to a large training dataset developed by the dynamic model. PCA is a fundamental piece of the leakage prediction algorithm developed in this research. In a simulation study, the designed leakage prediction algorithm is able to predict leakage using clean training and test data with a root mean square (RMS) error of less than 1%. Further algorithm development includes determining the best dynamic measurements to obtain, the amount of training data, a filter design for the raw experimental data, and training data manipulation. A simulation study shows that the signal combination that gives the best prediction performance is a combination of the pump pressure, control piston pressure, and the swashplate angle. This was confirmed by evaluating the leakage prediction performance with experimental pump response data. Having determined the optimal sensor data, the amount of training data is investigated. This was shown to improve from 100 samples and peak at 1000 samples. An optimization using experimental data was performed to determine the best filter to apply to the experimental response data. It was determined that a low pass filter with a cutoff frequency 10% below the piston pumping frequency gave the best leakage prediction results. This research includes a thorough investigation into the manipulation of the training data. The detailed optimal noise addition parameters give a predictive error of less than 20% using a signal combination of pump pressure, control piston pressure, and swashplate angle for experimental pump response data. Using just the pump and control piston pressure transients results in approximately 40% prediction error. Swashplate response data give conflicting results as the predictive error for the minimally worn pump is much different than the high wear pump (20% for severely worn). This research is an investigation into the feasibility of a load sensing axial piston pump condition monitoring device that measures case drain leakage via dynamic measurements. A comprehensive analysis is performed to optimize a leakage predictive algorithm and the design is tested in simulation as well as with experimental data and shows good potential