scholarly journals A Numerical Study on Pressure Variation in a Shock Tube by Changing the Diameter Ratio of Low-Pressure (Driven) to High-Pressure (Driver) Part

2016 ◽  
Vol 21 (4) ◽  
pp. 16-22
Author(s):  
YuanGang Wang ◽  
Chul Jin Kim ◽  
Chae Hoon Sohn ◽  
In-Seuck Jeung
Keyword(s):  
High Pressure ◽  
Shock Tube ◽  
Numerical Study ◽  
Low Pressure ◽  
Diameter Ratio ◽  
Pressure Variation ◽  
Pressure Driven

Pressure Variation in Low Pressure Side of Shell and Tube Heat Exchanger After Tube Rupture

2014 ◽  
Author(s):  
Ganesh S. Katke ◽  
M. Venkatesh ◽  
N. P. Gulhane
Keyword(s):  
High Pressure ◽  
Heat Exchanger ◽  
Low Pressure ◽  
Pressure Variation ◽  
Operating Pressure ◽  
Pressure Side ◽  
Tube Heat Exchanger ◽  
Analytical Algorithm ◽  
Shell And Tube ◽  
Design Pressure

This paper presents an analytical algorithm to determine the pressure variation on the Low Pressure side of a Shell and Tube Heat Exchanger (STHE) after a tube rupture and its validation using CFD simulation. STHEs are often used for exchanging heat between high-pressure (HP) and low-pressure (LP) fluids in the chemical process industry. In case tube rupture occurs in a STHE having a large pressure difference between HP and LP side, there is a risk of release of significant quantity of fluid from the HP side to the LP side. The consequent pressure build-up can lead to the failure of LP side pressure envelope. Generally, design pressure of the LP side is about 10–20% higher than the operating pressure of the LP side fluid, but well below the operating pressure on the HP side. There is no well-established methodology to design the LP side to withstand sudden release of high pressure fluid following a tube rupture. Three dimensional analyses were carried out using Computational Fluid Dynamics to study the pressure variation in LP side (shell side) of a Gas Cooler and to validate the results obtained from the analytical algorithm. It has been observed that the pressure on the LP side exceeds the design pressure instantaneously due to generation of a pressure pulse after tube rupture. This may lead to damage of LP envelope (shell) and internal structure of STHE.

scholarly journals Modeling of Pressure Exchanger for Energy Recovery on Trans Critical CO2 Refrigeration Cycle

2019 ◽  
Author(s):  
Ahmed Elatar ◽  
Kashif Nawaz ◽  
Brian Fricke ◽  
Vishaldeep Sharma
Keyword(s):  
High Pressure ◽  
Fluid Pressure ◽  
Low Pressure ◽  
Pressure Variation ◽  
Water Desalination ◽  
Working Fluid ◽  
Refrigeration System ◽  
Fluid Behavior ◽  
High Pressure Co2 ◽  
Contour Plots

Abstract Pressure exchanger is a device used to recover energy from high pressure working fluid in systems like Reverse Osmosis water desalination. The pressure exchanger enables the high-pressure fluid to transfer portion of its energy to the low-pressure fluid by transferring the fluid pressure. This working concept can be applied to systems where there is a significant pressure variation of the working fluid along the system. Trans critical CO2 refrigeration system is a good example for significant pressure variation during the flow path. The high-pressure CO2 exiting the condenser can be recovered by the low-pressure CO2 upstream of the compressor using a pressure exchanger to increase the system overall efficiency. The proposed research is to numerically simulate a prototype pressure exchanger for trans critical CO2 refrigeration system. The focus of this study is to understand the thermo-fluid behavior of the system when CO2 is used as the working fluid. Contour plots of velocity and pressure are presented for qualitative analysis.

Aerodynamic Interactions Between a High Pressure Turbine and the First Low Pressure Stator

2013 ◽  
Author(s):  
Pierre Gougeon ◽  
Ghislaine Ngo Boum ◽  
Francis Lebœuf
Keyword(s):  
Boundary Condition ◽  
High Pressure ◽  
Boundary Conditions ◽  
Numerical Study ◽  
Low Pressure ◽  
Single Stage ◽  
High Pressure Turbine ◽  
Low Pressure Turbine ◽  
Unsteady Rans ◽  
Rotating Boundary

This paper presents a numerical study on the interaction between a single-stage high-pressure turbine and the first vane row of a low-pressure turbine at aerodesign conditions. It focuses on the simulation of the flow within the inter-turbine duct and the loss generated in the downstream low-pressure vane. Former experiments provided steady and unsteady measurements in the duct between the high and the low-pressure turbines and after the low-pressure nozzle. A 3D unsteady RANS approach with phase-lagged boundary conditions is used to characterize the unsteady periodic effects developing in the inter-turbine channel and downstream in the low-pressure vane. For the numerical study, two different configurations were considered: a single stage high-pressure turbine configuration and a high-pressure rotor coupled with a low-pressure vane. For the second one, two inlet boundary conditions are considered upstream of the rotor: a circumferentially uniform boundary condition and a circumferentially non uniform rotating boundary condition. The resulting flow fields are compared within the intermediate duct. A harmonic Fourier analysis is carried out to underline the effects of upstream and downstream stator and the interaction with the high-pressure rotor. An unsteady Adamczyk decomposition within a plane located in the duct showed the influence of the different components and the levels of unsteadiness. Comparisons with experimental data show a reasonable good agreement.

Experimental and Numerical Study of Pressure in a Shock Tube

2016 ◽  
Vol 138 (4) ◽  
Author(s):  
Hassan A. Khawaja ◽  
Ramzi Messahel ◽  
Bruce Ewan ◽  
Souli Mhamed ◽  
Mojtaba Moatamedi
Keyword(s):  
High Pressure ◽  
Shock Tube ◽  
Numerical Study ◽  
Tube Diameter ◽  
Experimental Results ◽  
Orifice Plate ◽  
Orifice Diameter ◽  
Arbitrary Lagrangian Eulerian ◽  
Transient Stage ◽  
Constant Diameter

This paper presents the behavior of pressure in an air–water shock tube. In this work, high-pressure air (at 100 bar) interacts with water (at 1 atm ∼ 1 bar) through an orifice in a 100 mm constant diameter tube. The experiments are repeated with three different orifice plate diameters of 4, 8, and 15 mm. The variation of pressure during the transient stage is recorded in these experiments and it is found that with increasing orifice diameter, the amplitude of the pressure increases linearly with time when all other conditions are unchanged. The same phenomenon is simulated using the ls-dyna® software using an arbitrary Lagrangian Eulerian (ALE) method to solve the problem numerically. Simulations are made with a range of orifice diameters. The experimental results confirm the validity of the simulations algorithm. The simulations also demonstrated that the pressure behaves linearly with orifice diameter only when orifice diameter is less than 15% of the tube diameter.

Numerical Study of Hot Gas Ingestion Into an Engine Type High-Pressure Turbine Rotor-Stator Cavity

2001 ◽  
Author(s):  
Ingo Förster ◽  
Eckhard Martens ◽  
Winfried-Hagen Friedl ◽  
Dieter Peitsch
Keyword(s):  
High Pressure ◽  
Numerical Study ◽  
Turbine Rotor ◽  
Pressure Variation ◽  
Jet Engine ◽  
Hot Gas ◽  
Turbine Disc ◽  
Air System ◽  
Engine Type ◽  
Circumferential Pressure

The rims of high pressure turbines in aeroengines are sealed with air via the internal air system. This sealing is required to avoid occurrence of hot gas ingestion into the rotor-stator cavities. Due to a rapid decrease of turbine disc life at higher temperatures, such ingestion would present a hazard to the integrity of the discs and subsequently to the safety of the aircraft. One of the driving factors for ingestion is the circumferential pressure variation downstream of vanes and blades due to the aerodynamic wakes. Small ingestion cavities close to the annulus are commonly used to damp down this pressure variation. Substantial ingestion into these cavities is permitted. The actual sealing of the rotor-stator cavity itself is accomplished with a secondary seal. A numerical simulation of the flow in an engine type rotor-stator cavity was carried out using a commercial CFD code. The cases studied comprise relevant features as rotor-stator and ingestion cavities, leakage across rotor blade shanks and circumferential pressure variation downstream of an NGV. The simulation was carried out at relevant engine temperatures and pressures. The paper will firstly present the effects of a variation of the rim sealing mass flow on the flow field, ingestion and temperature increase in the cavity. These results were solely gained by computational means. For validation of a new air system design, engine tests on the BR715 jet engine have been performed. The data measured in these tests not only serve for certification purposes, but also may be used as input for CFD calculations. Thus, the experimental data was the baseline for comparison with the results from the present study.

Aerodynamic Interactions Between a High-Pressure Turbine and the First Low-Pressure Stator

2014 ◽  
Vol 136 (7) ◽  
Author(s):  
Pierre Gougeon ◽  
Ghislaine Ngo Boum
Keyword(s):  
Boundary Condition ◽  
High Pressure ◽  
Boundary Conditions ◽  
Numerical Study ◽  
Low Pressure ◽  
Flow Fields ◽  
Single Stage ◽  
Navier Stokes ◽  
High Pressure Turbine ◽  
Rotating Boundary

The accurate prediction of turbines performance and flow fields requires the assessment of unsteady numerical simulations. This paper presents a numerical study on the interaction between a single-stage high-pressure turbine and the first vane row of a low-pressure turbine. It focuses on the simulation of the flow within the interturbine duct and the loss generated in the downstream low-pressure vane. Former experiments provided steady and unsteady measurements in the interturbine duct and after the low-pressure vane. A 3D unsteady Reynolds-averaged Navier–Stokes (URANS) approach with phase-lagged boundary conditions is used to characterize the unsteady periodic effects in the interturbine channel and downstream in the low-pressure vane. For the numerical study, two different configurations are considered: a single-stage high-pressure turbine configuration and a high-pressure rotor coupled with a low-pressure vane. For the second one, two inlet boundary conditions are implemented upstream of the rotor: a circumferentially uniform boundary condition and a circumferentially nonuniform rotating boundary condition. The resulting flow fields are compared within the intermediate duct. A harmonic Fourier analysis is carried out to underline the effects of the high-pressure rotor. An unsteady Adamczyk decomposition of the flow field within the duct gives the influence of the different components and the levels of unsteadiness. Comparisons with experimental data show a reasonable good agreement.

scholarly journals Shock Tube Combustion Analysis

2021 ◽  
Author(s):  
Claudio Marcio Santana ◽  
Jose Eduardo Mautone Barros
Keyword(s):  
High Pressure ◽  
Shock Tube ◽  
Soybean Oil ◽  
Ignition Delay ◽  
Delay Time ◽  
Ignition Delay Time ◽  
Low Pressure ◽  
Pressure Chamber ◽  
Ignition Delay Times ◽  
Delay Times

The shock tube is a metal tube that the gas at low pressure and high pressure are separated by a diaphragm. When the diaphragm (make of material copper and aluminum) breaks on predetermined conditions (high pressure in this case) produces shock waves that move from the high-pressure chamber (known the compression chamber or Driver section) for low pressure chamber (known the expansion chamber or Driven section). The objective of this work is the correlate the ignition delay times of convectional Diesel and Biodiesel from soybean oil measured in a shock tube. The results were correlated with the cetane number of respective fuels and compared with the ignition delay times of Diesel and Biodiesel with cetane numbers of known. The ignition delay time of biodiesel from soybean oil was approximately three times greater than the ignition delay time of convectional Diesel. The contribution of this work is that it shows why pure biodiesel should not be used as substitutes for Diesel compression ignition engines without any major changes in the engines.

Fouling Is the Beginning: Upcycling Biopolymer-Fouled Substrates for Fabricating High-Permeance Thin-Film Composite Polyamide Membranes

2020 ◽  
Author(s):  
Ruobin Dai ◽  
Hongyi Han ◽  
Tianlin Wang ◽  
Jiayi Li ◽  
Chuyang Y. Tang ◽  
...  
Keyword(s):  
Thin Film ◽  
High Pressure ◽  
End Of Life ◽  
Water Purification ◽  
Low Pressure ◽  
Polymeric Membranes ◽  
Membrane Recycling ◽  
Film Composite ◽  
Thin Film Composite ◽  
First Time

Commercial polymeric membranes are generally recognized to have low sustainability as membranes need to be replaced and abandoned after reaching the end of their life. At present, only techniques for downcycling end-of-life high-pressure membranes are available. For the first time, this study paves the way for upcycling fouled/end-of-life low-pressure membranes to fabricate new high-pressure membranes for water purification, forming a closed eco-loop of membrane recycling with significantly improved sustainability.

Sign in / Sign up

Export Citation Format

Share Document