Attenuating characteristics of a multi-element buffer bottle in an aircraft piston pump

2015 ◽  
Vol 231 (10) ◽  
pp. 1791-1803 ◽  
Author(s):  
Lei Li ◽  
Kok-Meng Lee ◽  
Xiaoping Ouyang ◽  
Huayong Yang
Keyword(s):  
Pressure Pulsation ◽  
Design Method ◽  
Energy System ◽  
Piston Pump ◽  
Orifice Diameter ◽  
Attractive Alternative ◽  
Geometrical Parameters ◽  
Chamber Volume ◽  
Fluid Filter ◽  
Discharge Pressure

Pressure pulsation of an aircraft piston pump and accompanying vibrations are often sources of unreliability and fatigue of an aircraft hydraulic energy system. To reduce discharge pressure pulsation, a buffer bottle is usually installed inside the pump for space consideration that generally restricts its chamber volume resulting in a high working frequency range usually well exceeding the pressure pulsation frequencies corresponding to the normal operating speed range of the pump and hard to be adjusted once installed. To meet this challenge, this paper presents a method for designing a multi-element buffer bottle as an integrated fluid filter network formed by sub-elemental circuits (consisting of orifice, pipe and T-off) that can be assembled in an aircraft piston-pump. This design method of a compact fluid filter network is illustrated with a practical example based on a multi-element buffer bottle. Based on impedance models, results of an in-depth numerical investigation analyzing the effects of different buffer-bottle designs, geometrical parameters and adjustable orifice dimensions on pressure pulsation attenuation are discussed. The method for tuning the operating resonant frequency of a multi-element buffer bottle for pressure attenuation using a changeable orifice diameter is demonstrated experimentally confirming the buffer bottle as an attractive alternative to the conventional methods based on large-volume chambers.

scholarly journals A Two-Round Optimization Design Method for Aerostatic Spindles Considering the Fluid–Structure Interaction Effect

2021 ◽  
Vol 11 (7) ◽  
pp. 3017
Author(s):  
Qiang Gao ◽  
Siyu Gao ◽  
Lihua Lu ◽  
Min Zhu ◽  
Feihu Zhang
Keyword(s):  
Optimal Design ◽  
Optimization Design ◽  
Design Method ◽  
Fluid Structure Interaction ◽  
Design Procedure ◽  
Design Parameters ◽  
Geometrical Parameters ◽  
Fluid Structure ◽  
Structure Interaction ◽  
Aerostatic Spindle

The fluid–structure interaction (FSI) effect has a significant impact on the static and dynamic performance of aerostatic spindles, which should be fully considered when developing a new product. To enhance the overall performance of aerostatic spindles, a two-round optimization design method for aerostatic spindles considering the FSI effect is proposed in this article. An aerostatic spindle is optimized to elaborate the design procedure of the proposed method. In the first-round design, the geometrical parameters of the aerostatic bearing were optimized to improve its stiffness. Then, the key structural dimension of the aerostatic spindle is optimized in the second-round design to improve the natural frequency of the spindle. Finally, optimal design parameters are acquired and experimentally verified. This research guides the optimal design of aerostatic spindles considering the FSI effect.

scholarly journals Load of the slipper-swash plate kinematic pair of an axial piston pump

2018 ◽  
Vol 157 ◽  
pp. 08013 ◽  
Author(s):  
Tadeusz Złoto ◽  
Konrad Kowalski
Keyword(s):  
Piston Pump ◽  
Geometrical Parameters ◽  
Kinematic Pair ◽  
Axial Piston Pump ◽  
Swash Plate ◽  
Axial Piston

The paper presents problems related to the twisting moment of the slipper. The load of the slipper and the piston has been presented and the complex formula of twisting moment of the slipper has been established. Achieved results has been presented graphically. The conducted research has indicated that the value of the twisting moment relays on both the exploitation and geometrical parameters.

scholarly journals Strain and Curvature Stability Enhanced SMF Introduction

2017 ◽  
Vol 6 (1) ◽  
pp. 63
Author(s):  
S. Makouei
Keyword(s):  
Refractive Index ◽  
Optical Fiber ◽  
Design Method ◽  
Single Mode ◽  
Effective Area ◽  
Refractive Index Profile ◽  
Curvature Radius ◽  
Geometrical Parameters ◽  
Small Curvature ◽  
Bending Loss

In this paper, the strain insensitive single mode optical fiber with low nonlinear effects and ultra low bending loss (BL), appropriate for small curvature radius installation, is presented. The suggested design method is based on the reverse engineering which evaluates the refractive index profile considering proper mode field diameter (MFD) value. Then, so as to attain the desired bending loss and strain response for the optical fiber, the optimization tool of the evolutionary genetic algorithm (GA) is employed to determine the optical and geometrical parameters of the structure. In the first designed fiber, the calculations for BL, MFD, effective area (Aeff), and effective refractive index (neff) sensitivity to strain in the well-known wavelength of 1.55 µm are 0.0018 dB per each turn of 5 mm curvature radius, 8.53 µm, 58 µm2, and 4.5 × 10-8 µɛ-1, respectively. Furthermore, the effect of placing raised outer cladding in the fiber structure is investigated which exhibits the MFD of 8.63 µm, 0.0093 dB BL for single turn of 5 mm radius, and 87 µm2 Aeff at 1.55 µm. In this case the strain sensitivity of 6.7 × 10-8 µɛ-1 is calculated for the neff. The mentioned effective area is magnificently large in the domain of bend insensitive fibers. In the meantime, the designed structures are insensitive to strain which is a crucial feature in applications with small curvature radius.

Effects of Sleeve Parameters On Cavitation Control Performance in Steam Trap Valves

2021 ◽  
Author(s):  
Chang Qiu ◽  
Zhi-xin Gao ◽  
Zhi-jiang Jin ◽  
Jin-yuan Qian
Keyword(s):  
Power Systems ◽  
Optimization Design ◽  
Thermal Power ◽  
Orifice Diameter ◽  
Geometrical Parameters ◽  
Piping System ◽  
Cavitation Performance ◽  
Installation Angle ◽  
Steam Trap ◽  
Cavitation Intensity

Abstract The steam trap valve is used in thermal power systems to pour out condensate water and keep steam inside. While flowing through steam trap valves, the condensate water can easily reach cavitation, which may cause serious damage to the piping system. In this paper, in order to control cavitation inside steam trap valves, effects of sleeve parameters, including orifice diameter, installation angle and thickness, are investigated using a cavitation model. The pressure, velocity and vapor distribution inside valves are analyzed and compared for different sleeve geometrical parameters. The total vapor volumes are also predicted and compared. The results show that the sleeve parameters have a significant influence on the cavitation intensity and cavitation vapor distributions. Specifically, the orifice diameter of the sleeve has much larger effect on each aspect than that of other two geometrical parameters of the sleeve. The improved geometrical parameters of the sleeve are determined to suppress the cavitation inside the valve. The sleeve with smaller diameter orifices, higher installation angle (maximum 80°) and higher thickness is recommended in practice for better anti-cavitation performance. The work is of significance for cavitation control and the optimization design of steam trap valves.

Cavitation in a high-speed aviation axial piston pump over a wide range of fluid temperatures

2021 ◽  
pp. 095765092110469
Author(s):  
Qun Chao ◽  
Zi Xu ◽  
Jianfeng Tao ◽  
Chengliang Liu ◽  
Jiang Zhai
Keyword(s):  
Temperature Effects ◽  
Pressure Pulsation ◽  
Piston Pump ◽  
Limiting Factors ◽  
Fluid Temperature ◽  
Cfd Model ◽  
Axial Piston Pump ◽  
Wide Range ◽  
Fluid Properties ◽  
Axial Piston

The axial piston pump in aerospace applications needs to operate over a wide range of fluid temperatures from −54°C to 135 °C. The fluid properties at such extreme temperatures will significantly affect the cavitation that is one of the major limiting factors for the efficiency and reliability of aviation axial piston pumps. However, it appears that very little of the existing literature studies the effects of extreme fluid temperatures on the pump cavitation. This paper aims to examine the temperature effects on the cavitation in an aviation axial piston pump. First, we develop a three-dimensional (3D) transient computational fluid dynamics (CFD) model to investigate the pump cavitation and validate it experimentally. Second, we use the validated CFD model to investigate the temperature effects on the pump cavitation by changing the fluid properties including viscosity, density, and bulk modulus. The numerical results show that low fluid temperature makes the aviation axial piston pump suffer serious cavitation due to high viscosity, leading to delivery flow breakdown, unacceptable pressure pulsation, and delayed pressure built up. In contrast, high fluid temperatures have minor effects on the cavitation although they increase the pressure pulsation and built-up time slightly.

Experimental Study of Chamber Volume Effect on Bubble Formation From Orifice Plates Submerged in Water

2018 ◽  
Author(s):  
Omkar S. Gokhale ◽  
Milind A. Jog ◽  
Raj M. Manglik
Keyword(s):  
Experimental Study ◽  
Bubble Size ◽  
Bubble Formation ◽  
Orifice Plate ◽  
Orifice Diameter ◽  
Equilibrium Contact Angle ◽  
Growth Time ◽  
Size And Shape ◽  
Chamber Volume ◽  
Gas Chamber

Experimental study of air bubble formation from orifice plates submerged in water pools has been carried out. Air is forced through the orifice by supplying it to a chamber connected to the orifice plate. The chamber volume plays an important role in determining the bubble growth time as well as bubble size and shape at departure. The effect of chamber volume is generally correlated in term of a dimensionless parameter, capacitance number (Nc), which is proportional to the chamber volume and is inversely proportional to the square of the orifice diameter. To better understand and characterize this effect, an experimental study is performed using ten orifice plates of diameter ranging from 0.61 mm to 2.261 mm with six different chamber volumes between 12 cc and 59 cc with the corresponding capacitance numbers varying from 0.2 to 19. The shape and size of the bubble are captured using high speed videography. The orifice plate material is acrylic glass which has an equilibrium contact angle of 38° with pure water. It was observed that the value of critical capacitance number or Nc above which the bubble evolution is affected by the gas chamber volume, is around 0.85. The bubbles are more spherical in shape, and the growth time is significantly smaller. Also, at high capacitance number (Nc > 7), the air flow in the bubble is so high that the bubble departs with a sharp apex and has a large volume. Above Nc > 10, the chamber effects plateau and further increase in gas chamber volume does not alter bubble size and shape at departure.

Atomization Characteristics of Effervescent Atomizer With Two-Aerator Tube

2004 ◽  
Author(s):  
Hyung Gon Kim ◽  
Shuichi Torii ◽  
Toshiaki Yano ◽  
Kyu Keun Song
Keyword(s):  
Mass Flow Rate ◽  
Mass Flow ◽  
Flow Rate ◽  
Orifice Diameter ◽  
Nozzle Orifice ◽  
Chamber Volume ◽  
Mixing Chamber ◽  
Mean Diameter ◽  
Effervescent Atomizer ◽  
Atomization Characteristics

An experimental study was conducted to investigate the atomization characteristics of spray from the effervescent atomizer, which has two-aerator tube. The atomization characteristics were examined through the influence of ALR (Air-to-Liquid Ratio) and the changes of atomizer geometry (nozzle orifice diameter, diffusion angle, mixing chamber volume). PDPA (Phase Doppler Particle Analyzer) was used to evaluate the SMD (Sauter Mean Diameter) and droplet velocity. During the experiments, the mass flow rate of liquid was kept constant at 2.8g/s and the mass flow rate of atomizing air was changed from 0.2 to 0.6g/s. Experimental results showed that SMD is not a linear function of ALR. While SMD is very sensitive to the changes of ALR, the changes of atomizer geometry have little effect on droplet mean diameter. As the effervescent atomizer with two-aerator tube is insensitive to the changes of atomizer geometry, it is expected that the effervescent atomizer with two-aerator tube is capable of requirements of many applications, without the drawbacks of atomization characteristics.

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