Thermodynamic characteristics of counter flow and cross flow plate fin heat exchanger based on distributed parameter model. (25th January 2023)

• Record Type: Journal Article
• Authors: Liu, Yuce; Li, Ke; Wen, Jian; Wang, Simin
• Is Part Of: Applied thermal engineering. Volume 219(2022)Part B
• Publication Date: 2023-01-25
• Subjects: Plate fin heat exchanger -- Longitudinal heat conduction -- Effectiveness -- Heat transfer amount -- Pump power; Heat engineering -- Periodicals; Heating -- Equipment and supplies -- Periodicals; Periodicals; 621.40205
• DOI: 10.1016/j.applthermaleng.2022.119542
• Languages: English
• ISSNs: 1359-4311

Abstract

Highlights: Distributed parameter models of counter and cross flow PFHE are constructed. Effect of longitudinal heat conduction on heat transfer performance of counter flow PFHE is investigated. Effect of configuration and operation parameters on heat transfer amount and pump power of cross flow PFEH is studied. Improved structures of cross flow PFHE are proposed. Abstract: The distributed parameter models of counter flow and cross flow plate fin heat exchanger (PFHE) are constructed to investigate their thermodynamic characteristics. In practical application, the cold end of PFHE may be directly connected to the cold equipment. Therefore, the effect of longitudinal heat conduction (LHC) under different thermal boundary conditions set on two ends of the separating plates (SPs) is investigated based on the model of counter flow PFHE. It is found that LHC effect transmits the effect of boundary condition on two ends of the SPs into the inner domain of PFHE. The LHC effect on the heat transfer performance of PFHE is positive when setting appropriate boundary condition on two ends of the SPs. When considering LHC, compared with the adiabatic boundary conditions on two ends of the SPs, the effectiveness of constant wall temperature boundary conditions increases by 31.7 ∼ 35.8 %, and the effectiveness of constant heat flux boundary conditions increases by 22.8 %. The model of cross flow PFHE is used to investigate the effect of configuration and operation parameters on the heat transfer amount and the pump power. The cross flow PFHE is optimized to arrive at the maximization of heat transfer amount per unit pump power (HTPUP). In the three-stream cross flow PFHE studied, the heat transfer amount almost doesn't change when the xz projected area is maintained and one projected length ( z side length) is changing. The pump power is the lowest and the HTPUP is the largest when z side length of PFHE ( z side is the flow direction of the fluid with large mass flowrate) is 0.15 ∼ 0.2 m.