Experimental research on control strategy of expansion valve based on R134a/lubricating oil flow pattern identification
QIN Jingna
YIN Lumei
FAN Xiaowei
JU Fujun
LI Zhaohui
ZHANG Yu
ZHANG Zhihui
Abstract：Using the gray level co-occurrence matrix,the variations of characteristic parameters of horizontal and vertical flow patterns of R134a/lubricating oil at the evaporator outlet in a heat pump system with the change of superheat degree were studied under various operating conditions.And the feasibility of implementing automatic expansion valve control through flow pattern recognition was al-so analyzed.The results demonstrate that for all three conditions,the entropy of horizontal flow pat-terns in the identification region Ⅰ exhibits more consistent variation with superheat degree compared to vertical flow patterns.under condition 2,the entropy of horizontal flow patterns in the identifica-tion region Ⅰ-4 initially increases and then decreases with rising superheat degree,and it shows more significant variation,thus the entropy is chosen as the optimal characteristic parameter for horizontal flow pattern identification;the horizontal flow patterns have different optimal identification regions under the operating conditions,and the entropy shows smooth variations with superheat degree in these optimal identification regions;the target control range for entropy is determined,and a prelimi-nary expansion valve control strategy based on intelligent recognition of flow pattern is proposed.
Keywords：grayscale co-generation matrixflow pattern identificationheat pumpcontrol strategy
Publication Date：2025-04-25
Online Publishing Date：2025-08-15(First online date of this platform, not the publication date of the document)
Pages：7( 60-66 )