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Augmentation Techniques And Condensation Inside Advanced Geometries
Published in Satish G. Kandlikar, Masahiro Shoji, Vijay K. Dhir, Handbook of Phase Change: Boiling and Condensation, 2019
Moo Hwan Kim, Vijayaraghavan Srinivasan, Ramesh K. Shah
Plate-fin heat exchanger. Much of the work done on predicting the pressure drop for vertical downflow condensation in serrated and plain plate-fin passages remains industrial proprietary information. The correlation approach for predicting pressure losses is discussed by Robertson et al. (1986). It is found that the frictional component of the pressure drop in compact condenser passages is predicted using the same basic approach as that for the smooth round tubes (for example, the Chisholm type correlation). However, the round tube correlation cannot be directly applied to the rectangular passages. As shown in Eq. (24.2-11), ϕ1 is found to depend both on X and Relo (and therefore mass flux G). Hence, there is a need to take into account the mass flux dependency in the correlation for ϕ1, particularly for rectangular passages as shown in Eqs. (24.2-12) and (24.2-13).
Applications: Engineering with Ceramics
Published in David W. Richerson, William E. Lee, Modern Ceramic Engineering, 2018
David W. Richerson, William E. Lee
The layered design involves a plate–fin concept such as illustrated in Figure 3.8. Note that alternating layers have flow channels at 90° to each other to provide a cross-flow pattern between the hot gases and cold gases. The “plates” separate the hot-gas layers from the cold-gas layers. The “fins” provide high surface area to enhance heat transfer efficiency and to provide structural strength. As an alternative to the rectangular channels, the fins can be in a sinusoidal pattern to yield a corrugated appearance similar to cardboard. A plate–fin heat exchanger can be relatively compact compared to tubular heat exchanger.
Recent Progress on High Temperature and High Pressure Heat Exchangers for Supercritical CO2 Power Generation and Conversion Systems
Published in Heat Transfer Engineering, 2023
The diffusion-bonded plate-fin heat exchanger is a type of compact heat exchanger that consists of a stack of alternate flat plates and corrugated fins, and the joining is accomplished by diffusion bonding to form a solid block of metal with flow passages passing through it. The thermal operational limits of the plate fin style cores depend on the type of materials used and are generally more suitable to lower pressure applications up to 200 bars, which are lower than those of printed circuit style cores [46]. Plain, perforated, offset-strip, louvered, wavy fin geometries have been used in the design of plate-fin heat exchangers for heat transfer enhancement. Plate-fin heat exchangers have been applied in power and energy industries, and a growing research activity is under way on the development of diffusion-bonded plate-fin heat exchangers for supercritical CO2 cycles. The supercritical CO2 flows through the internal fin-supported passages and distributes and collects at the two ends of the header blocks, while the hot air or flue gas flow crosses between the fins. However, studies on general fin performance and applicable fin selection strategies at high temperature and high pressure are limited.
Research on low-temperature performance of plate-fin hydrogen preheater for a proton-exchange membrane fuel cell
Published in International Journal of Green Energy, 2021
Qinguo Zhang, Zheming Tong, Shuiguang Tong, Zhewu Cheng
In order to avoid the damage of the film electrode caused by freezing or undercooling at the anode inlet during cold start-up, a hydrogen preheating structure was designed, as shown in Figure 1. The function of the preheating structure is to heat hydrogen through the heat generated by the electric heating system to improve the adaptability of hydrogen fuel cells to low-temperature environment. The foregoing fuel cell cold-start anode rapid heating system includes a hydrogen transfer pipe, a fuel cell stack, a heater, a heat exchanger, a thermometer, and the control system. The heater is arranged on the cooling liquid pipeline to convert the electric energy into the thermal energy of the cooling liquid through the energy storage battery and heats the hydrogen in the anode side flow channel of the stack through a heat exchanger. In addition, the heater is controlled to turn on and off according to the temperature inside the stack measured by the thermometer. The plate-fin heat exchanger used in the preheating system has the advantages of high heat transfer coefficient, compact structure, and small footprint.
Enhancement of Heat Transfer for Plate Fin Heat Exchangers Considering the Effects of Fin Arrangements
Published in Heat Transfer Engineering, 2018
In Figure 12, cold fluid temperature variations on the channel top surface for fin types of B and C under parallel and counter flow are shown. When the development distance of the first temperature variation is 0.1065 m from the beginning of a flat channel, it is 0.045 m for a channel with fin type of C under parallel flow. As can be seen in Figure 12, for both flow types the temperature gradient distance for fin type of C improves earlier than fin type of B which has lower temperature values of cold fluid. Besides, it is clearly seen that for fin types of B and C larger temperature values are obtained compared to a flat channel. Consequently, it can be said that the use of fins effectively improves the heat transfer performance of a plate fin heat exchanger by enhancing the currents of turbulence and heat transfer surface area.