Characterization and Modeling of the Dynamic Behavior of a Liquid-Vapor Phase Change Actuator

2007 ◽  
Author(s):  
H. Bardaweel ◽  
R. Richards ◽  
L. Weiss ◽  
C. Richards ◽  
M. Anderson
Keyword(s):  
Phase Change ◽  
Vapor Phase ◽  
Dynamic Performance ◽  
Lumped Parameter Model ◽  
Frequency Range ◽  
Two Phase ◽  
Lumped Parameter ◽  
Phase Fluid ◽  
Fft Analysis ◽  
Liquid Vapor

In this work a study of the dynamic performance of a liquid-vapor phase change actuator is presented. The actuator consists of a cavity filled with a two phase fluid bounded by a thin membrane into which heat is added and a cover slip which is displaced by the expansion of the vapor. An experimental actuator was designed so that a parametric study of geometry and operation parameters could be conducted. A lumped parameter model of the system was developed to predict forces and displacements produced by the addition of heat. The input to the model is the heat and the output is the displacement of the actuator. FFT analysis of the actuator deflection and heat input are performed. This procedure allows the measurement of the transfer function between actuator displacement as output and heat as input over a frequency range of 10 to 500 Hz. These data are compared to the predictions of the lumped parameter model. Agreement is favorable.

Atomistic and macroscopic characterization of nanoscale thin film liquid-vapor phase change phenomena

2021 ◽  
Vol 170 ◽  
pp. 107159
Author(s):  
Md Muntasir Alam ◽  
Md Shajedul Hoque Thakur ◽  
Mahmudul Islam ◽  
Mohammad Nasim Hasan ◽  
Yuichi Mitsutake ◽  
...  
Keyword(s):  
Thin Film ◽  
Phase Change ◽  
Vapor Phase ◽  
Nanoscale Thin Film ◽  
Phase Change Phenomena ◽  
Liquid Vapor

Modeling of Vapor Compression Cycles for Multivariable Feedback Control of HVAC Systems

1997 ◽  
Vol 119 (2) ◽  
pp. 183-191 ◽  
Author(s):  
Xiang-Dong He ◽  
Sheng Liu ◽  
Haruhiko H. Asada
Keyword(s):  
Feedback Control ◽  
Phase Interface ◽  
Heat Pumps ◽  
Lumped Parameter Model ◽  
Vapor Compression ◽  
Two Phase ◽  
Lumped Parameter ◽  
Fan Speed ◽  
Linearized Model ◽  
Multivariable Feedback

This paper presents a new lumped-parameter model for describing the dynamics of vapor compression cycles. In particular, the dynamics associated with the two heat exchangers, i.e., the evaporator and the condenser, are modeled based on a moving-interface approach by which the position of the two-phase/single-phase interface inside the one-dimensional heat exchanger can be properly predicted. This interface information has never been included in previous lumped-parameter models developed for control design purpose, although it is essential in predicting the refrigerant superheat or subcool value. This model relates critical performance outputs, such as evaporating pressure, condensing pressure, and the refrigerant superheat, to actuating inputs including compressor speed, fan speed, and expansion valve opening. The dominating dynamic characteristics of the cycle around an operating point is studied based on the linearized model. From the resultant transfer function matrix, an interaction measure based on the Relative Gain Array reveals strong cross-couplings between various input-output pairs, and therefore indicates the inadequacy of independent SISO control techniques. In view of regulating multiple performance outputs in modern heat pumps and air-conditioning systems, this model is highly useful for design of multivariable feedback control.

scholarly journals Lumped parameter modeling of hybrid magnetomotive force electromechanical valve actuator

2020 ◽  
Author(s):  
Muhammad Adnan Alvi ◽  
Zhaohui Zhang ◽  
Jawad Aslam ◽  
Saad Ali ◽  
Emad Uddin ◽  
...  
Keyword(s):  
Energy Consumption ◽  
Magnetic Force ◽  
Dynamic Performance ◽  
Lumped Parameter Model ◽  
Magnetomotive Force ◽  
Lumped Parameter ◽  
Low Energy Consumption ◽  
Camless Engines ◽  
Mathematical Equations ◽  
Variable Valve

Abstract In this study, an innovative hybrid permanent magnet (PM)/electromagnet (EM) magneto-motive force (MMF) actuator is proposed for variable valve timing camless engines. The proposed design provides a large magnetic force with low energy consumption (startup and valve holding), PM demagnetization isolation, and improved transient response. The modified hybrid valve actuator (MHVA) was designed in ANSYS Maxwell software and validated empirically by prototype. A lumped parameter model (LPM) based on mathematical equations is developed to approximate Finite Element Method (FEM) and experimental results. The LPM is divided into electrical, magnetic and mechanical subsystems that are developed and integrated in MATLAB software. The comparative analysis of LPM, FEM and empirical results confirmed improved dynamic performance and energy consumption.

Sign in / Sign up

Export Citation Format

Share Document