Analysis of the Effect Made by the Variable Heat Capacity on the Characteristics of Pressure Pulsations in a High-Speed Air Intake Using the RANS/ILES Method

2020 ◽  
Vol 12 (3) ◽  
pp. 403-412
Author(s):  
D. A. Lyubimov
Keyword(s):  
Heat Capacity ◽  
High Speed ◽  
Pressure Pulsations ◽  
Variable Heat ◽  
Air Intake

High Speed Electric Actuator Designs for Improved Air Intake

2007 ◽  
Author(s):  
Loussert Guillaume ◽  
Angleviel Didier ◽  
Biwersi Stéphane ◽  
Andrieux Gaël
Keyword(s):  
High Speed ◽  
Electric Actuator ◽  
Air Intake

Mixed Compression Air-Intake Design for High-Speed Transportation

2021 ◽  
pp. 139-162
Author(s):  
Can Çıtak ◽  
Tekin Aksu ◽  
Özgür Harputlu ◽  
Gerhard-Wilhelm Weber
Keyword(s):  
High Speed ◽  
Air Intake

scholarly journals A New Simulation Model for Vertical Spiral Ground Heat Exchangers Combining Cylindrical Source Model and Capacity Resistance Model

Energies ◽  
2020 ◽  
Vol 13 (6) ◽  
pp. 1339 ◽  
Author(s):  
Takao Katsura ◽  
Takashi Higashitani ◽  
Yuzhi Fang ◽  
Yoshitaka Sakata ◽  
Katsunori Nagano ◽  
...  
Keyword(s):  
Heat Capacity ◽  
Simulation Model ◽  
High Speed ◽  
Approximate Equation ◽  
Source Model ◽  
Calculation Model ◽  
Ground Heat Exchangers ◽  
Ground Source ◽  
Equivalent Length ◽  
Cylindrical Source

Considering the heat capacity inside vertical spiral ground heat exchanger (VSGHEX) in the simulation is one of the most noteworthy challenge to design the ground source heat pump (GSHP) system with VSGHEXs. In this paper, a new simulation model for VSGHEXs is developed by combining the ICS model with the CaRM. The developed simulation model can consider the heat capacity inside VSGHEX and provide dynamic calculation with high speed and appropriate precision. In order to apply the CaRM, the equivalent length was introduced. Then, the equivalent length was approximated by comparing the results of the CaRM and the numerical calculation. In addition, the calculation model of the VSGHEX was integrated into the design and simulation tool for the GSHP system. The accuracy of the tool was verified by comparing with the measurements. The error between supply temperatures of the measurements and calculation is approximately 2 °C at the maximum. Finally, assuming GSHP systems with VSGHEXs, whose spiral diameter was 500 mm and depth was 4 m, were installed in residential houses in Japan, the required numbers of VSGHEXs were estimated. The results showed a strong correlation between the total heating or cooling load and the required number. Therefore, the required number can be estimated by using the simplified approximate equation.

Flow Characteristics on the Chute with a Concave Surface Influenced by the Air Intake of the Aerator

2011 ◽  
Vol 90-93 ◽  
pp. 2559-2563 ◽  
Author(s):  
Yi Min Xu ◽  
Hong Xuan Yang ◽  
Wei Zhao ◽  
Chun Ying Shen
Keyword(s):  
High Speed ◽  
Cavity Length ◽  
Flow Characteristics ◽  
Air Pressure ◽  
Concave Surface ◽  
Cavity Size ◽  
Jet Trajectory ◽  
Air Intake ◽  
Trajectory Equation ◽  
High Speed Flows

The flow characteristics of an aerator inserted on the chute with a concave surface is more complex than that of on the straight chute. The area of the air intake of the aerator is a very important factor which influences the cavity size of jet flow after the aerator, the air pressure in the cavity and air concentrations in high-speed flows along the chute. The present project focused on the air intake of an aerator inserted on a model chute with a concave surface. How the area of the air intake of the aerator and the radius of chute arc affect flow characteristics are investigated. The air pressure in the cavity was indirectly derived from the jet trajectory equation. It is demonstrated that the cavity length increases with, and the air pressure in it decreases with the increasing of the air intake area at first, and then it remains unchangeable for a discharge even though the air intake area continues to increase.

Diesel Engine Turbocharger Stabilized With Novel Tilting Pad Bearing Design

2012 ◽  
Author(s):  
R. Gordon Kirk ◽  
Matthew Enniss ◽  
Daniel Freeman ◽  
Andrew Brethwaite
Keyword(s):  
High Speed ◽  
Fluid Film ◽  
Pressure Pulsations ◽  
The Past ◽  
Fluid Film Bearings ◽  
Film Instability ◽  
Tilting Pad ◽  
Full Speed ◽  
Bearing Design ◽  
Engine Testing

Many high speed turbochargers operate with limit cycle vibration as a result of fluid-film instability. This problem has been under investigation for the past seven years. Only now has a turbocharger with fluid film bearings been run to full speed and loaded, with essentially no bearing induced sub-synchronous vibration. The goal of this research was to have a stable synchronous response with a minimum of non-synchronous contribution excited only by the engine dynamics and exhaust pressure pulsations. Previous papers have documented experimental results of the fixed geometry bearing designs. This paper documents a new, modified tilting pad bearing concept that has replaced the fixed geometry bushings with minimal modifications to the stock bearing housing. The summary of the on-engine testing over the past year is documented in this paper.

Experimental Study on Pressure Transients With Cavitation in Low Pressure Water-Hydraulic Pipeline

2018 ◽  
Author(s):  
Dan Jiang ◽  
Cong Ren ◽  
Qing Guo
Keyword(s):  
High Speed ◽  
Gas Bubbles ◽  
Video Camera ◽  
Low Pressure ◽  
Pressure Pulsations ◽  
Pressure Transients ◽  
Pressure Transducers ◽  
High Speed Video Camera ◽  
Pressure Water ◽  
Water Hydraulic

In this study, pressure transients are triggered by a steel ball, which is released from an upstream reservoir to hit a valve seat and shut off water flow in a horizontal straight copper pipeline. The pressure pulsations, cavitation and gas bubbles growth and collapse in the low pressure water-hydraulic pipeline are recorded by two pressure transducers and a high speed video camera, respectively. In addition, the influences of initial volume of gas bubbles in water and instant leakage in valve are investigated. The experimental results indicate that increasing initial gas bubble volume in water and the instant leakage of the valve will help to reduce magnitudes and numbers of pressure peaks during pressure transients. Then methods to reduce pressure pulsations in pipelines are put forward.

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