Several nozzle concepts that promise a gain in performance over existing conventional nozzles are discussed in this paper. It is shown that signie cant performance gains result from the adaptation of the exhaust e ow to the ambient pressure. Special attention is then given to altitude-adaptive nozzle concepts, which have recently received new interest in the space industry. Current research results are presented for dual-bell nozzles and other nozzles with devices for forced e ow separation and for plug nozzles with external freestream expansion. In addition, results of former research on nozzles of dual-mode engines such as dual-throat and dual-expander engines and on expansion ‐dee ection nozzles are shown. In general, e ow adaptation induces shocks and expansion waves, which result in exit proe les that are quite different from idealized one-dimensional assumptions. Flow phenomena observed in experiments and numerical simulations during different nozzle operations are highlighted, critical design aspects and operation conditions are discussed, and performance characteristics of selected nozzles are presented. The consideration of derived performance characteristics in launcher and trajectory optimization calculations reveal signie cant payload gains at least for some of these advanced nozzle concepts.

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Advanced Rocket Nozzles.

The increasing demand for higher performance in rocketlaunchers promotes the development of nozzles with higherperformance, which basically is achieved by increasing theexpansion ratio. However, th ...

/pdf/supersonic-flow-separation-with-application-to-rocket-engine-1u19nxum57.pdf

Supersonic Flow Separation with Application to Rocket Engine Nozzles

Injection and Atomization Propellant Injection Systems and Processes Dynamics of Liquid Rocket Injectors Atomization of Coaxial-Jet Injectors Atomization of Impinging-Liquid Jets Disintegration and Distortion of Liquid Streams Combustion and Ignition Modeling of Liquid-Propellant Combustion in Rocket Engine Combustor Liquid-Propellant Droplet Vaporization and Combustion Droplet Cluster Behavior in Dense and Dilute Regions of Sprays Supercritical Combustion CARS Measurements in Cryogenic LOX-GH2 Jet Flames Propellant Ignition and Flame Propagation Nozzle Concepts, Design, and Optimization Rocket Engine Nozzle Concepts Nozzle Design and Optimization Thrust Chamber Dynamics, Heat Transfer, and Performance Simulation and Analysis of Thruster Chamber Flowfields: Storable Propellant Rockets Simulation and Analysis of Thrust Chamber Flowfields: Cryogenic-Propellant Rockets Scaling Techniques in Liquid Rocket Engine Combustion Devices Testing Thrust Chamber Cooling and Heat Transfer Assessment of Thrust Chamber Performance Aspects of Engine System Design Thermodynamic Power Cycles for Pump-Fed Liquid Rocket Engines Tripropellant Liquid Rocket Engine Technology Oxidizer-Rich Preburner Technology for Oxygen/Hydrogen Full Flow Cycle Applications

Liquid rocket thrust chambers : aspects of modeling, analysis, and design

Effects of rainfall on aircraft aerodynamics

Simulation of road vehicle natural environment in a climatic wind tunnel

Unarmed plastic projectiles can be equipped with small axisymmetric cavities for the generation of intense tones that are useful in training maneuvers. Attention is presently given to the simulation of rainfall in an airstream and the effect of rain droplet impingement on the nose of projectiles, and especially to any penetration or accumulation of water at the base of the cavity that might increase the fundamental cavity frequency and/or reduce the intensity of sound production during rain conditions.

Rain simulation studies for high-intensity acoustic nose cavities

Aspects are examined of an investigation by the Marshall Space Flight Center into the conceptual feasibility of increasing the thrust performance of the Space Shuttle Main Engine (SSME) by using a conical nozzle extension fitted with an ablative insert in order to achieve a low-cost, near-term gain in payload The ablating insert would provide a controlled increase in nozzle expansion ratio during launch and early climbout (first 30-60 seconds) so as to reduce thrust loss from nozzle over-expansion in the lower atmosphere Summaries are given of JPL studies in the area of: defining the near-wall flow environment in the extended nozzle insert region; selecting potential insert materials; conceptualizing an extension/insert geometrical configuration; and identifying future experimental efforts necessary to verify the feasibility of the concepts

Thrust Improvement with Ablative Insert Nozzle Extension

Studies conducted to determine structure and composition of cenospheres. Burn more slowly than original fuel, contribute to deposits, high-temperature corrosion, emissions of particles, and reduced efficiency of combustion in oil-fired furnaces and boilers, accounting 3 percent of original fuel in droplets. Contributes to efforts to burn fuel oil more completely to avoid deleterious effects of incomplete combustion.

Characteristics Of Cenospheres

A TWO-STAGE gas turbine combustor concept based upon a very fuel-rich partial-oxidation stage is being explored for broadening the combustion margin between ultralow emissions and the lean stability limit. Combustion and emission results are presented for a series of experiments where a simulated partial-oxidation product gas was used in a premix combustor operated with inlet air state conditions typical of cruise power for high-performance aviation engines (1.2 MPa and 728 K). Ultralow NOX, CO, and HC emissions and an extended lean burning limit (relative to single-stage baseline operation) were achieved simultaneously.

Richard M. Clayton

Papers

Rain simulation studies for high-intensity acoustic nose cavities

Thrust Improvement with Ablative Insert Nozzle Extension

Characteristics Of Cenospheres

Emission Characteristics of a Combustor Burning Simulated Partial-Oxidation Product Gas