Numerical Study of Flow Maldistribution in Multi-Plate Heat Exchangers Based on Robust 2D Model

Brenk, Arkadiusz; Płuszka, Paweł; Malecha, Ziemowit

doi:10.3390/en11113121

Cited by 14 publications

(16 citation statements)

References 25 publications

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“…In the currently developed numerical model the computational domain was divided into five separated regions as shown in Figure 5. This can be perceived as a simplified geometrical feature of a plate heat exchanger (PHE) [40,41], which usually consists of a large number of thin plates separated by a small gap. Consequently, the PHE channels contain alternately hot and cold fluid.…”

Section: Numerical Modelmentioning

confidence: 99%

Theoretical and Numerical Analysis of Freezing Risk During LNG Evaporation Process

2019

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The liquid natural gas (LNG) boiling process concerns most LNG applications due to a need for regasification. Depending on the pressure, the equilibrium temperature of LNG is 112–160 K. The low boiling temperature of LNG makes the vaporization process challenging because of a large temperature difference between the heating medium and LNG. A significant risk included in the regasification process is related to the possibility of solid phase formation (freezing of the heating fluid). A solid phase formation can lead to an increase in pressure loss, deterioration in heat transfer, or even to the destruction of the heat exchanger. This prompts the need for a better understanding of the heat transfer during the regasification process to help avoid a solid phase formation. The present research is focused on the investigation of the mutual interactions between several parameters, which play a significant role in the regasification process. The research is based on a zero-dimensional (0D) model, which was validated through the comparison with a state-of-the-art Computational Fluid Dynamics (CFD) model. This made fast calculations and the study of the risk of freezing for a wide range of parameter space possible, including the LNG boiling regime. The boiling regime of LNG was shown to be a key factor in determining the risk of freezing.

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Section: Numerical Modelmentioning

confidence: 99%

Theoretical and Numerical Analysis of Freezing Risk During LNG Evaporation Process

2019

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“…Flow maldistribution in the inlet header and its effects on the thermal performances were investigated using theoretical analysis, computational fluid dynamic (CFD) simulations, and experimental testing technologies in the past few decades [7,8]. Lalot [9] calculated the outlet velocity ratio to represent the flow maldistribution, and the results indicated that the gross flow maldistribution led to a loss of effectiveness of about 7% for counterflow heat exchangers and up to 25% for crossflow exchangers.…”

Section: Of 14mentioning

confidence: 99%

Improvement of Flow Distribution by New Inlet Header Configuration with Splitter Plates for Plate-Fin Heat Exchanger

Peng

et al. 2020

Energies

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The pressure drop increases along with the decrease in the flow maldistribution in the two-stage distributing inlet headers of a plate-fin heat exchanger. To solve this issue, we proposed a new inlet header configuration with splitter plates to decrease the flow maldistribution and pressure drop simultaneously. We used computational fluid dynamic technology to analyze the flow properties in the inlet header configuration and calculated the flow maldistribution degree of the outlet channels and the pressure drop in the inlet header. We performed a sensitivity analysis between the structural parameters, the flow maldistribution degree, and the pressure drop. We determined the optimum values of the structural parameters (the construction of transition duct, the number of splitter plates, the inclined angle of outermost plates, the height of splitter plates, the height of inlet header, etc.), and acquired the optimum configuration of the improved inlet header. Compared with the traditional inlet header, the flow maldistribution degree and pressure drop decreased by 91.5% and 40.9%, respectively, using the proposed improved inlet header with splitter plates, which performed better than the conventional two-stage distribution inlet header.

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“…The adsorber design has to increase heat transfer while also decreasing intra-and interparticle mass transfer resistance [20]. Moreover, the flow maldistribution should be minimized [23]. According to [21], adsorption kinetics are strongly reduced in the case of excessive adsorbent thickness.…”

Section: Heat Exchangers: New Types Of Adsorption Bedsmentioning

confidence: 99%

Experimental Study of Performance Improvement of 3-Bed and 2-Evaporator Adsorption Chiller by Control Optimization

et al. 2019

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The main challenge facing adsorption cooling technology is low Coefficient of Performance (COP), which becomes a key factor of the commercialization of this technology. This paper presents the results of modifications, aiming to increase COP, applied to the control software of a prototype three-bed two-evaporator adsorption chiller. Changes were mainly related to the sequence of the switching valves and had no influence on the hardware of the chiller. The sequence changes enabled the introduction of heat recovery and mass regeneration. Moreover, the precooling process was improved. The applied modifications not only resulted in significant improvement of the chiller's COP, but also improved the cooperation adsorption unit heating source, which is of great importance in case of district heating supply. The improvement was also observed concerning such operational aspects as noise and vibrations. In the authors' opinion, the presented modifications can be introduced to most exploited adsorption chillers and could potentially lead to similar improvements in performance.Energies 2019, 12, 3943 2 of 17 Methods of Improving COP of Adsorption ChillerThe issue of COP improvement of adsorption chillers is the subject of much research, which focuses on two main fields of study: Improvements via hardware modification and via software modification. Hardware modifications mainly consist of the proper selection of working pairs, the optimization of the adsorption beds [8], and the general system design. Software modifications reported in the literature optimize the switching time and cycle allocation. Some of the optimization methods, like the application of heat or mass recovery, usually require both hardware and software modifications. Working PairsThe appropriate selection of the working pair was reported in [9,10] as a crucial factor influencing the COP of adsorption chillers. Therefore, much reported research is related to adsorption working pairs and their properties [10]. The most popular pairs are microporous silica gel and water, zeolite and water (including alumino-silicate zeolites) [11,12], and Y-type zeolite with methanol or ethanol combinations [9,13]. Moreover, some novel adsorption working pairs are investigated, that is (silico) aluminophosphate-water, consolidated adsorbents such as LiBr-silica-ethanol or water, CaCl 2 -silica and water, and activated carbon with ethanol, methanol or water [9].Each adsorption working pair has unique properties that make it possible to obtain good performance in the conditions considered. For example, water-based pairs cannot be applied to achieve temperatures lower than 0 • C (due to water's freezing point). Some of the adsorbates, like methanol, are harmful, and its application would probably require additional safety procedures. An overview of working pairs was presented by [14]. Other important factors which must be considered are the expense and availability of the selected adsorption working pair.

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Numerical Study of Flow Maldistribution in Multi-Plate Heat Exchangers Based on Robust 2D Model

Cited by 14 publications

References 25 publications

Theoretical and Numerical Analysis of Freezing Risk During LNG Evaporation Process

Theoretical and Numerical Analysis of Freezing Risk During LNG Evaporation Process

Improvement of Flow Distribution by New Inlet Header Configuration with Splitter Plates for Plate-Fin Heat Exchanger

Experimental Study of Performance Improvement of 3-Bed and 2-Evaporator Adsorption Chiller by Control Optimization

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