Influence of Hole-to-Hole Interaction on the Acoustic Behavior of Multi-Orifice Perforated Plates

2021 ◽  
Author(s):  
Alireza Javareshkian ◽  
Alexis Dancelme ◽  
Hongyu Chen ◽  
Thomas Sattelmayer
Keyword(s):  
Wave Propagation ◽  
Resonance Frequency ◽  
Interaction Effect ◽  
Gas Turbines ◽  
Perforated Plate ◽  
Wall Region ◽  
Optimized Design ◽  
Perforated Plates ◽  
Proposed Model ◽  
Hole Interaction

Abstract A key factor for developing low-emission combustion systems in modern gas turbines and aero-engines is the acoustic liner’s optimized design. Several models are available in the literature for the acoustic impedance of perforated acoustic liners. Most of these impedance models neglect the interaction effect between the orifices. In practice, the orifices are generally closely distributed such that the interactions between acoustic radiation from neighboring orifices can affect their acoustical behavior. The hole-to-hole interaction effect may change the resonance frequency of the resonator due to the nonplanar wave propagation in the cavity, the orifices in the perforated plate, and the near-wall region in the combustor. Considering this effect may help to predict the resonance frequency of the resonator accurately. In this work, a three-dimensional (3D) analytical approach is developed to account for the nonplanar wave propagation in the cavity and orifices on the perforated plate. The present study employs the proposed 3D analytical method to determine the hole-to-hole interaction end-correction of multi-orifice perforated plates. Additionally, the hole-to-hole interaction end-correction from a series of perforated plates with different orifice radii and spacings is obtained via the Finite Element Method (FEM). Perforated plate specimens with different center-to-center hole spacing are tested using an impedance tube. Experimental results show that the resonance frequency is shifted towards a lower frequency with decreasing holes’ spacing. The resulting model is compared with the experiments and the end-correction models available in the literature. The comparison shows that the available end-correction models cannot capture the hole-to-hole interaction effect, which is observed in experiments. In contrast, the proposed model can reproduce measurements with high quality. The resulting model demonstrates that the acoustic end-correction length for orifices is closely related to the perforated plate’s porosity ratio and orifice radius. The proposed model is readily applicable in the design of multi-orifice perforated plates.

Influence of Hole-To-Hole Interaction On the Acoustic Behavior of Multi-Orifice Perforated Plates

2021 ◽  
Author(s):  
Alireza Javareshkian ◽  
Alexis Dancelme ◽  
Hongyu Chen ◽  
Thomas Sattelmayer
Keyword(s):  
Resonance Frequency ◽  
Interaction Effect ◽  
Gas Turbines ◽  
Acoustic Radiation ◽  
Three Dimensional ◽  
Perforated Plate ◽  
Optimized Design ◽  
Perforated Plates ◽  
Aero Engines ◽  
Hole Interaction

Abstract The acoustic liner's optimized design is critical for developing low-emission combustion systems in modern gas turbines and aero-engines. Several models are available in the literature for the acoustic impedance of perforated acoustic liners. Most of these models neglect the interaction effect between orifices. Generally, orifices are closely distributed such that the interactions between acoustic radiation from neighboring orifices can affect their acoustical behavior. The hole-to-hole interaction effect may change the resonator's resonance frequency due to the nonplanar wave creation in the vicinity of area jumps. Considering this effect may help to predict the resonator's resonance frequency accurately. In this work, a three-dimensional (3D) analytical approach is developed to consider the nonplanar wave creation in the cavity and orifices on the perforated plate. The proposed 3D analytical method is employed to determine the hole-to-hole interaction end-correction of multi-orifice perforated plates. The hole-to-hole interaction end-correction from a series of perforated plates with different orifice radii and spacings is obtained via the Finite Element Method (FEM). Perforated plates with different center-to-center hole spacing are tested using an impedance tube. Experimental results show a shift in the resonance frequency towards a lower frequency with decreasing holes' spacing. The comparison with the experiments shows that the available end-correction models in the literature cannot capture the hole-to-hole interaction effect observed in experiments. In contrast, the proposed model can reproduce measurements with high quality.

Optimization of SCR inflow uniformity based on CFD simulation

Open Physics ◽  
2020 ◽  
Vol 18 (1) ◽  
pp. 1168-1177
Author(s):  
Ke Sun ◽  
Haiyang Zhao ◽  
Kui Zhao ◽  
Da Li ◽  
Shuzhan Bai
Keyword(s):  
Pressure Drop ◽  
Cfd Simulation ◽  
Catalytic Reduction ◽  
Perforated Plate ◽  
Optimized Design ◽  
Original Design ◽  
Perforated Plates ◽  
Scr Catalyst ◽  
Catalyst Carrier ◽  
The Cost

Abstract The inflow uniformity before selective catalytic reduction (SCR) catalyst carrier is a major issue for DeNO x capability of diesel engine after-treatment. Through the construction of the numerical model and CFD simulation of six perforated plate variations with different structural and positional characteristics, the influence of perforated plates on the uniformity of the airflow velocity at the inlet of the SCR catalyst carrier was analyzed. Comparison of different perforated plate variations shows that the encircling flow is a major hindrance to achieve higher inflow uniformity. Enclosed flow passage can remove the encircling flow and increase inflow uniformity at the cost of increased pressure drop. Rational layout of the perforated plate can achieve uniformity increase, while decrease pressure drop. High-velocity exhaust coupled with larger holes can improve both uniformity and pressure drop. The uniformity index increased from 97.6% of the original design to 98.7% of the optimized design, while pressure drop increased from 11.20 to 12.09 kPa. Weighing the relationship between inflow uniformity and pressure drop is an issue worthy of attention.

scholarly journals Influence of Holes Manufacture Technology on Perforated Plate Aerodynamics

Materials ◽  
2021 ◽  
Vol 14 (21) ◽  
pp. 6624
Author(s):  
Joanna Grzelak ◽  
Ryszard Szwaba
Keyword(s):  
Gas Turbines ◽  
Perforated Plate ◽  
Flow Characteristics ◽  
Aerodynamic Characteristics ◽  
Physical Models ◽  
Experimental Investigations ◽  
Perforated Plates ◽  
Flow Losses ◽  
Large Numbers

Transpiration flow is a very important and still open subject in many technical applications. Perforated walls are useful for the purpose of “flow control”, as well as for the cooling of walls and blades (effusive cooling) in gas turbines. We are still not able to include large numbers of holes in the numerical calculations and therefore we need physical models. Problems are related also to the quality of the holes in perforated plates. The present transpiration analysis concerns with experimental investigations of the air flow through perforated plates with microholes of 125 and 300 µm diameters. A good accordance of the results with other experiments, simulations and theory was obtained. The received results very clearly show that technology manufacturing of plate holes influences on their aerodynamic characteristics. It turned out that the quality of the plate microholes using laser technology and, consequently, the shape of the hole, can affect the flow losses. Therefore, this effect was investigated and the flow characteristics in both directions were measured, i.e., for two plate settings.

Application of an Element-free Galerkin Method to Water Wave Propagation Problems

2014 ◽  
Vol 60 (1-4) ◽  
pp. 87-105 ◽  
Author(s):  
Ryszard Staroszczyk
Keyword(s):  
Wave Propagation ◽  
Galerkin Method ◽  
Present Model ◽  
Free Surface Elevation ◽  
Element Free Galerkin Method ◽  
Plane Flow ◽  
Element Free Galerkin ◽  
Proposed Model ◽  
Sloping Bed ◽  
Element Free

Abstract The paper is concerned with the problem of gravitational wave propagation in water of variable depth. The problem is solved numerically by applying an element-free Galerkin method. First, the proposed model is validated by comparing its predictions with experimental data for the plane flow in water of uniform depth. Then, as illustrations, results of numerical simulations performed for plane gravity waves propagating through a region with a sloping bed are presented. These results show the evolution of the free-surface elevation, displaying progressive steepening of the wave over the sloping bed, followed by its attenuation in a region of uniform depth. In addition, some of the results of the present model are compared with those obtained earlier by using the conventional finite element method.

Ship Component in Hull Optimization

2005 ◽  
Vol 39 (2) ◽  
pp. 39-46 ◽  
Author(s):  
Kent Davey
Keyword(s):  
Gas Turbines ◽  
Optimized Design ◽  
Power Train ◽  
Load Demand ◽  
Hull Optimization ◽  
Size Number ◽  
Component Identification ◽  
Electric Ship ◽  
Mission Profile ◽  
System Volume

This document outlines an optimization to define the size of the components in the power train of an electric ship, specifically one appropriate for an 80 MW Destroyer. The objective is to minimize the volume of the system, including the fuel. The size, number and speed of the gas turbines, the electric generators, and the power electronics are considered as unknowns in the analysis. At the heart of the procedure is the power mission profile. The gas turbine is by far the most important component in terms of influence on system volume. Integral to its selection is the specific fuel consumption as a function of power and turbine size. The proposed procedure outlines a nested optimization to define both the best spread of turbines as well as the proper scheduling with load demand. Including fuel in the system volume is the key to meaningful component identification. The optimized design has a system volume 603.5 m3 smaller than the base configuration, assuming both systems employ load scheduling among turbines. An optimized design can save as much as 600 m3.

Peak-Shaving Ratio Analysis of the Natural Gas Combined Heat and Power Plant With Distributed Peak-Shaving Heat Pumps

2017 ◽  
Author(s):  
Xiling Zhao ◽  
Xiaoyin Wang ◽  
Tao Sun
Keyword(s):  
Natural Gas ◽  
Heat Source ◽  
Heat Pump ◽  
Gas Turbines ◽  
Heat Load ◽  
Operating Cost ◽  
Heat Pumps ◽  
Optimized Design ◽  
Peak Shaving ◽  
Gas Price

Distributed peak-shaving heat pump technology is to use a heat pump to adjust the heat on the secondary network in a substation, with features of low initial investment, flexible adjustment, and high operating cost. The paper takes an example for the system that uses two 9F class gas turbines (back pressure steam) as the basic heat source and a distributed heat pump in the substation as the peak-shaving heat source. The peak-shaving ratio is defined as the ratio of the designed peak-shaving heat load and the designed total heat load. The economic annual cost is taken as a goal, and the optimal peak-shaving ratio of the system is investigated. The influence of natural gas price, electricity price, and transportation distance are also analyzed. It can provide the reference for the optimized design and operation of the system.

High Speed Flow through Perforated Plates

1960 ◽  
Vol 64 (590) ◽  
pp. 103-105
Author(s):  
P. G. Morgan
Keyword(s):  
Pressure Drop ◽  
High Speed ◽  
Perforated Plate ◽  
Wire Mesh ◽  
Flow Conditions ◽  
High Speed Flow ◽  
Perforated Plates ◽  
Speed Flow ◽  
Flow Through ◽  
Points Of View

The flow through porous screens has been widely studied from both the theoretical and experimental points of view. The most widely used types of screen are the wire mesh and the perforated plate, and the majority of the literature has been concerned with the former. Several attempts have been made to correlate the parameters governing the flow through such screens, i.e. the pressure drop, the flow conditions and the geometry of the mesh.

scholarly journals THE STUDY OF ACOUSTIC CHARACTERISTICS OF THE PERFORATED AND HOMOGENOUS PLATES WITH SIMILAR GEOMETRICAL DIMENSIONS

Akustika ◽  
2019 ◽  
Vol 32 ◽  
pp. 79-82
Author(s):  
Valery Kirpichnikov ◽  
Lyudmila Drozdova ◽  
Alexei Koscheev ◽  
Ernst Myshinsky
Keyword(s):  
Resonant Frequency ◽  
Acoustic Radiation ◽  
Perforated Plate ◽  
Acoustic Characteristics ◽  
Resonant Frequencies ◽  
Perforated Plates ◽  
Resonance Frequencies ◽  
Flexural Vibrations ◽  
Geometrical Dimensions

The resonance frequencies of the flexural vibrations, input vibration excitability and acoustic radiation of the homogeneous and perforated plates were investigated. It is established that the average reduction range of the lower resonant frequency of flexural vibrations of the tested plates with the holes virtually coincides with the predictive estimate. The levels of the input vibration excitability of the perforated plate at the lower resonant frequencies exceeded the levels at the corresponding frequencies of the homogeneous plates greater than the calculated value. The levels of resonance acoustic radiation of the perforated plate were significantly less than of the homogeneous one.

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