Nozzles.pdf

2013

The main objective of the work is to analyse the performance and flow characteristics of convergent divergent nozzle and also to compare the numerical values of the two methods i.e "HIT & TRIAL METHOD" AND "ANALYTICAL METHOD". In this paper we have determine the location and strength of normal shock wave in the divergent portion of the nozzle under varying operating conditions and with different nozzle geometry. KEYWORD: Mach number, Sub-sonic, Super-sonic, Sonic, Compressible flow, Throat. I. NTRODUCTION A nozzle is a relatively simple device, just a specially shaped tube through which hot gases flow. However, the mathematics, which describes the operation of the nozzle, takes some careful thought. Nozzles come in a variety of shapes and sizes. Simple turbojets, and turboprops, often have a fixed geometry convergent nozzle as shown on the left of the figure. Turbofan engines often employ a co-annular nozzle. The core flow exits the centre nozzle while the fan fl...

IRJET, 2020

A nozzle is a very essential device that is used to control character of the fluid. The main purpose of the nozzle is to increase the velocity in one way or another. De Laval nozzle is a converging-diverging nozzle which has the ability to convert the chemical energy (high pressure) into kinetic energy (high velocity and low pressure). De-Laval nozzle has mainly 3 parts such as throat, diverging part, and converging part. Expansion in C-D nozzle has been studied and analyzed by experimentation moreover as numerically by numerous researchers with an objective to optimize the performance beneath given conditions. Within the gift work, supersonic flow through the rocket nozzle has been simulated mistreatment numerical methodology. The analysis has been performed keeping the same input and according to the shape of the nozzle. Our objective is to investigate the best suit nozzle which gives high exit velocity among the different cross-sections considered. The main aim of this paper is to a proper comparison with theoretical data to determine the behavior of fluid during the movement of fluid inside the nozzle. Therefore CFD analysis is being done using ANSYS 16. The paper contains a proper analysis of the convergent-divergent nozzle. Analysis of Mach number and velocity is done inside the nozzle

2013

Thrust-vectoring flight control is a leading-edge technology now being implemented in production aircraft such as the F-22, Su-37 and MiG 35. It significantly increases aircraft maneuverability and capability through enabling the use of jet-deflection as an alternative or enhancement to conventional aircraft flight control. Analytical modeling of thrust-vectoring nozzles has been at best fragmentary in publicly available literature in the past. For robust nozzle modeling not only the internal fluid mechanics need to be considered, but the dynamic geometry of the nozzle as well as the influence on the forces obtained from the jet by the flight velocity and angle of attack of the aircraft. With the fervent research into vertical flight capabilities as in the Joint Strike Fighter program, among other aircraft, the influence of the ground effect on the jet must also be considered. In all of this, the foundation of analysis lies in the understanding and modeling of aircraft nozzle perfor...

A nozzle is a device that is used to provide the way and direction to gases to come out of the combustion chamber. The nozzle is a device that is used to convert pressure and thermal energy into useful kinetic energy. A rocket nozzle can be used to manage and control the speed flow of pressure and steam being exhausted .rocket nozzle purpose is to convert high pressure, high-temperature gas into a high velocity, low temperature, and pressure. This paper had an analysis of the flow in the nozzle using the software ANSYS 16. The study is being carried out to have knowledge about flow inside the nozzle when the divergent section of the nozzle is being diverted or change to a certain angle using 2-d modeling to carry out the result and effects of the nozzle. The angle will make the effect on all the aspects of nozzle such as Mach number, static pressure, velocity, and temperature. The throat and inlet diameter of supersonic begin remain the same.

Shock Waves, 2014

The flow in a planar overexpanded nozzle with a slope discontinuity is studied numerically by means of two-(2D) and three-dimensional (3D) Reynolds-averaged Navier-Stokes simulations and is compared to experimental results. The nozzle pressure ratios (NPR) vary from 1.6 to 10. A good agreement is found between experimental and numerical results and two configurations are observed: under a certain critical NPR, the flow is shown to be asymmetrical with respect to the nozzle axis, while it is perfectly symmetrical for higher NPRs. The value of the critical NPR is found to be very dependent on the turbulence model. Finally, an hysteresis phenomenon is evidenced since the NPR at which the change of flow configuration occurs is different whether the NPR is increasing or decreasing in the nozzle.

International Journal of Science and Research, 2024

De Laval nozzle is a converging-diverging (CD) nozzle that can convert chemical energy with high pressure into kinetic energy with high velocity and low pressure. Manipulating variables such as area ratio and backpressure govern the flowing nature at the nozzle outlet to have either a supersonic flow or the existence of shock waves. This work reported a comprehensive flow simulation in a typical supersonic converging-diverging nozzle. This study is concerned with the study of the flow nature in the CD when the backpressure ratio was 10 kPa and 15 kPa for the given design of the nozzle. Mach number was supersonic for the pressure of 10 kPa. However, there was normal shock at the outlet with the Mach number reducing to 1 in case of 15 kPa backpressure. The pressure and density have been lowered, and velocity has been drastically increased at the outlet, producing greater thrust in the case of jet engines. The models were designed and analyzed using the ANSYS Fluent program. The results obtained from the ANSYS Fluent program were compared with the theoretical value calculated using isentropic flow equations for a nozzle.

This project develops a computer code which uses the Method of Characteristics and the Stream Function to define high efficiency nozzle contours for isentropic, inviscid, irrotational supersonic flows of any working fluid for any user-defined exit Mach number. The contours are compared to theoretical isentropic area ratios for the selected fluid and desired exit Mach number. The accuracy of the nozzle to produce the desired exit Mach number is also checked. The flow field of the nozzles created by the code are independently checked with the commercial Computational Fluid Dynamics (CFD) code ANSYS-FLUENT. ANSYSFLUENT predictions are used to verify the isentropic flow assumption and that the working fluid reached the user-defined desired exit Mach number.

This paper presents the results of experimental studies conducted to study the base pressure field from a convergent nozzle to ascertain the effect of micro jets, the length to diameter ratio, Mach number and area ratio in a suddenly expanded flow. The Mach numbers of the present study are 0.2, 0.4, 0.6, 0.8 and 0.9, respectively. From the results it is found that the micro jets are effective. The area ratio (ratio of area of suddenly expanded duct to nozzle exit area) studied are 2.56, 3.24, 4.84 and 6.25. The L/D ratio of the sudden expansion duct varies from 10 to 1, and tests were conducted for L/D 10, 8, 6, 5, 4, 3, 2 and 1. To study the quality of flow in the enlarged duct wall pressure was measured and it is found that the flow field remains undisturbed in the presence of micro jets.

2020

The flow in an Over-Expanded Nozzle is subjected to shock waves leading to the unsteady separation of the boundary layer. Free detachment may be followed by a restricted detachment. During the expansion regime in propellant nozzles, several physical phenomena are encountered: supersonic jet, jet separation, adverse pressure gradient, shock wave, turbulent boundary layer, highly compressible mixture layer, return flow, large scale turbulence. These very complex phenomena can considerably affect the performance of the nozzle. The numerical investigation was performed by the CFD-FASTRAN search code, using the k-w SST model as the turbulence model. The calculation is performed by solving the Navier-Stokes equations of two-dimensional compressible turbulent flow. It is based on the study of the fluidic vectorization phenomenon of the thrust of a double-injection convergent-divergent supersonic conical nozzle. The study is based on the effect of the ratio of NPR pressures with SPR = 1 on ...