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For complex engineering problems, multidisciplinary design optimization (MDO) techniques use some disciplines that need to be run several times in different modules. In addition, mathematical modeling of a discipline can be improved for each module. The purpose of this paper is to show that multi-modular design optimization (MMO) improves the design performances in comparison with MDO technique for complex systems.

MDO framework and MMO framework are developed to optimum design of a complex system. The nonlinear equality and inequality constrains are considered. The system optimizers included Genetic Algorithm and Sequential Quadratic Programming.

As shown, fewer design variables (optimization variables) are needed at the system level for MMO. Unshared variables are optimized in the related module when shared variables are optimized at the system level. The results of this research show that MMO has lower elapsed times (14 percent) with lower F-count (16 percent).

The monopropellant propulsion upper-stage is selected as a case study. In this paper, the efficient model of the monopropellant propulsion system is proposed. According to the results, the proposed model has acceptable accuracy in mass model (error < 2 percent), performance estimation (error < 6 percent) and geometry estimation (error < 10 percent).

The monopropellant propulsion system is broken down into the three important modules including propellant tank (tank and propellant), pressurized feeding (tank and gas) and thruster (catalyst, nozzle and catalysts bed) when chemical decomposition, aerothermodynamics, mass and configuration, catalyst and structure have been considered as the disciplines. The both MMO and MDO frameworks are developed for the monopropellant propulsion system.

IN the testing of rocket engines and engine components, such as thrust chambers and gas generators, the rocket engineer is regularly faced with the job of transferring cryogenic liquid propellants, using pressure feed from a storage tank, through a flow system and into the combustion device to be tested. At Rocketdyne, liquid oxygen, LOX, is quite commonly used as a propellant, and in the testing of engine components inert pressurants are usually used, for example, helium or nitrogen, although because of the cost and logistics, nitrogen is preferred. When gaseous nitrogen is used as the pressurant, we have repeatedly run into testing conditions which have resulted in condensation of nitrogen and subsequent mixing in the tanked liquid oxygen. This dilution of the liquid oxygen effects a loss of performance and imposes mechanical difficulty in maintaining a regulated propellant tank pressure.

The purpose of this paper is to artificially construct a functional surface with self-propulsion flow characteristics for the directional transportation of propellant in surface tension tanks.

In this study, a method to enhance the propulsion efficiency by using functional surfaces of self-propulsion performance was proposed. Superhydrophilic wedged-groove with the superhydrophobic background was fabricated and the self-propulsion capacity was verified.

It is found that the self-propulsion capacity is related to the divergence angle of the wedged-groove in the hydrophilic area, and the velocity of the droplets on the deflector plate is the largest with the divergence angle of 4°; the temperature gradient field formed by the condensing device at the nozzle can accelerate the droplet outflow from the tank.

Realization of this idea provides an accurate control strategy for the complex flow process of propellant in plate surface tension tanks, which could enhance the efficiency of the tension tank significantly.

Few aircraft engine facilities are capable of handling large high by‐pass ratio turbofans and it is hoped that other airlines will place contracts at Prestwick.

IT is well known that war gives a great impetus to development in many fields, not least of which is that of aircraft propulsion. Such was the case in World War II, when great strides were made, but it is interesting to note that the pace has hardly slackened in the years following its conclusion. This is perhaps because of the ‘cold’ war which took its place, or perhaps because the introduction of jet propulsion has stimulated thought and action in realms beyond the dreams of the piston engine era. Whatever the cause, the results are apparent and this is a suitable moment to look back and measure the progress of the past seven or eight years.

Materials and particularly metals for use in producing modern aircraft and space vehicles must have the ability to withstand damage, and this requirement becomes increasingly important. For example, if the materials used have high mechanical strength, corrosion‐resistance and tensile strength, they do not automatically become ideal choices. The properties more specifically asked for are the ability of the metals to withstand fracture on impact and also the degree to which they are likely to propagate cyclic cracks.

ROCKET and ramjet engines have not the universal application that gas turbines command and possibly on this account they have not had, until recent years, the development effort which gave such amazing results in turbine powered aircraft. Nevertheless, they have demonstrated quite dramatically in various parts of the world that they are power plants to be reckoned with. In Great Britain, their value for aircraft was appreciated somewhat belatedly and events have since decreed that the promise they showed should be smothered before it could become a vital fact. On the other hand their importance for missiles was realized at the conclusion of the 1939–45 war, but again they were not encouraged on anything like the scale that present events show would have been justified. Because of this lack of encouragement, British rockets and ramjets, instead of leading the world, as do gas turbines, are struggling hard to provide a modest rate of progress.

An Assessment of the Basic Design and Performance Based on a Heavily Retouched Photograph of a Large Ballistic Missile which was published in the December 4, 1962, edition of Kransnaya Zvezda (‘Red Star’). FOR the first time in any open literature source, the December 4, 1962, edition of Kransnaya Zvezda or Red Star, the daily newspaper of the Soviet Department of Defence, carried a very heavily retouched photograph of a very large ballistic missile with a caption describing the missile as their strategic rocket ready for launch. This photograph of a large rocket had obviously been heavily retouched so that little of its detail construction was identifiable. The rocket itself appears to have been cut out and pasted on to a photograph of a winter scene (fig. 1).

The purpose of this paper is to introduce new and modified “staged combustion” cycles in the form of engineering algorithm as a possible propulsion contender for future aerospace vehicle to achieve the highest possible “total impulse” to “mass” of propulsion system.

In this regard, the mathematical cycle model is formed to calculate the engine’s parameters. In addition, flow conditions (pressure, temperature, flow rate, etc). in the chamber, nozzle and turbopump are assessed based on the results of turbo machinery power balance and initial data such as thrust, propellant mixture ratio and specifications. The developed code has been written in the modern, object-oriented C++ programming language.

The results of the developed code are compared with the Russian RD180 engine which demonstrates the superiority and capability of new “thermodynamic diagrams”.

This algorithm is under constraint to control the critical variation of combustion pressure, turbine rpm, pump cavitation and turbine temperature. It is imperative to emphasize that this paper is limited to “oxidizer-rich staged combustion” engines with “single pre-burner”.

This study sheds light on using fuel booster turbopump and the second-stage fuel pump to moderate the effect of cavitation on pumps which reduces tank pressure and, as a consequence, decreases the propulsion system weight.