The Research Of Flowfield Characteristics And Parameter Optimization Of Right-Angled Channel

The right angled flow passage as an pipe form in industry has been widely used in various fields,such as ventilation duct for air conditioning system,fluid heat exchange passage in heat exchange equipment,fluid transfer nets passage and internal channel of manifold block in hydraulic integrated system.The manifold block component of such a system is usually realized by drilling,boring and other mechanical processing methods resulting in numerous right-angled flow passages with cavities.The complicated flow field structure in the hydraulic manifold block increases the energy loss of the whole system,and affects the dynamic and static performance of the whole system and the energy utilization ratio.Therefore,reducing energy loss of manifold blocks is of great importance to energy saving in hydraulic systems.In this paper,theoretical analysis is combined with numerical simulation and experimental research,focusing on the subject of optimizing hydraulic manifold block.First,this study was conducted to investigate the flowfield characteristics of right-angled flow passage with various cavities and arc transition flow passage with various turning radius using the 2D-PIV technique in the typical hydraulic manifold block.Next,on the basis of the experimental model,a right-angled flow passage with cavity length L=50%D was selected from the tested model to establish a numerical model to simulate the three-dimensional flowfield.Seven eddy viscosity turbulence models were investigated in predicting the flowfield by comparing against the PIV measurement results.By defining the weight error function K,the S-A model was selected as the appropriate turbulence model.,Then,based on single factor analysis,a three-factor,three-level response surface numerical test was conducted to investigate the influence of flow passage connection type,cavity diameter and cavity length-diameter ratio on pressure loss,and verified that the optimal factor level of the right angled turning channel is similar in different speed conditions.The velocity streamline and total pressure loss coefficient distribution of the four typical turning flow passages are analyzed at the same speed.The variation law of the pressure loss coefficient of the four typical turning flow passages at different speeds is also analyzed.Finally,this paper reviewed the research conclusion,and determines the direction of the future research.