Compact Heat Exchangers

Kays, W. M.; London, A. L.; Eckert, E. R. G.

doi:10.1115/1.3644004

Cited by 1,177 publications

(1,099 citation statements)

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“…In particular, the effect of the Reynolds number on the Euler number is rather small for sufficiently high Reynolds numbers. In the region of interest, it is found that -5-Moreover, research on turbulent flow [6] has shown that the form loss coefficient is nearly independent of the Reynolds number at values above 5000, except within boundary layers.…”

Section: (\'^2'•' -\) = 0 (3-2)mentioning

confidence: 99%

Use of Hydraulic Models in Nuclear Reactor Design

Hetsroni¹

1965

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Section: (\'^2'•' -\) = 0 (3-2)mentioning

confidence: 99%

Use of Hydraulic Models in Nuclear Reactor Design

Hetsroni¹

1965

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“…The governing equations presented in this section are developed for cross-flow heat exchangers with one fluid mixed and the other unmixed, in accordance with Kays and London (1998). Figure 1 shows the temperature variation for a single-pass cross-flow mixed-unmixed heat exchanger, i.e., heat exchanger with one row.…”

Section: Governing Equations For the Cross-flow Heat Exchangermentioning

confidence: 99%

“…Vardhan and Dhar (1998) proposed a model that discretizes the coil into nodes along the tube-side path and carries out repetitive movement between the tube element entrance and exit, while simultaneously updating the values of the air stream properties. Each element uses an effectiveness computed by mixed-unmixed cross-flow ε-NTU relations (Kays and London, 1998) with the air side characterized by the minimum heat capacity rate. Corberán and Melón (1998) developed a model discretizing the tube path with a UA-log mean temperature difference local approach to test the R134a evaporation and condensation correlation.…”

Section: Introductionmentioning

confidence: 99%

Effectiveness-ntu computation with a mathematical model for cross-flow heat exchangers

Navarro

Cabezas‐Gómez²

2007

Braz. J. Chem. Eng.

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-Due to the wide range of design possibilities, simple manufactured, low maintenance and low cost, cross-flow heat exchangers are extensively used in the petroleum, petrochemical, air conditioning, food storage, and others industries. In this paper a mathematical model for cross-flow heat exchangers with complex flow arrangements for determining ε-NTU relations is presented. The model is based on the tube element approach, according to which the heat exchanger outlet temperatures are obtained by discretizing the coil along the tube fluid path. In each cross section of the element, tube-side fluid temperature is assumed to be constant because the heat capacity rate ratio C*=C min /C max tends toward zero in the element. Thus temperature is controlled by effectiveness of a local element corresponding to an evaporator or a condensertype element. The model is validated through comparison with theoretical algebraic relations for single-pass cross-flow arrangements with one or more rows. Very small relative errors are obtained showing the accuracy of the present model. ε-NTU curves for several complex circuit arrangements are presented. The model developed represents a useful research tool for theoretical and experimental studies on heat exchangers performance.

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“…Kays and London [2] provided experimental correlations for a wide range of configurations adopted in compact extended surface heat exchangers and presented test data on finned circular tubes. Ward and Young [3] developed heat transfer and pressure drop correlations for plain finned tubes with triangular pitch.…”

Section: Literature Reviewmentioning

confidence: 99%

Development of a new type of finned heat exchanger

Bošnjaković

Čikić²,

Muhič

et al. 2017

Teh. vjesn.

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Original scientific paper A new geometric form of fins (needle fins) for finned heat exchangers of gas-liquid type is described. It achieves a higher heat transfer coefficient and lower mass of the heat exchange surface relative to the heat exchangers with circular fins which in this case served as a basis for comparison. For the analysis of the heat transfer, the computational fluid dynamics analysis with ANSYS Fluent software was applied. Numerical simulation was performed for the round fins and fins with a new, innovative geometric shape at air flow speeds of 1 m/s to 5 m/s. The results of numerical simulations, with regard to the exchanged heat and pressure drop were verified by the correlations available in the literature and compared to the simulation results for tubes with innovative fins. Results show an increase in the amount of Nu from 20 % to 30 % for 2300 >Re > 12000 while reducing mass of heat exchange surfaces of 23,8 %.Keywords: finned heat exchanger; heat exchange; heat exchanger efficiency; needle fins; numerical simulation Razvoj novog tipa lamelnog izmjenjivača toplineIzvorni znanstveni članak Opisan je novi geometrijski oblik lamele (igličaste lamele) za orebrene cijevne izmjenjivače topline plin -tekućina pomoću kojeg se postiže veći koeficijent prijelaza topline, a time i manja masa izmjenjivačkih površina u odnosu na izmjenjivače topline s okruglim lamelama koji su u ovom slučaju poslužili kao baza za usporedbu. Za analizu izmjene topline i pada tlaka primijenjena je računalna dinamika fluida s programom ANSYS Fluent. Numerička simulacija provedena je za slučaj zagrijavanja zraka koji struji oko cijevi s lamelama novog geometrijskog oblika te oko cijevi s lamelama konvencionalnog kružnog oblika brzinama od 1 m/s do 5 m/s. Rezultati numeričke simulacije obzirom na izmijenjenu toplinu i pad tlaka za cijevi s okruglim lamelama provjereni su pomoću korelacija dostupnih u literaturi te su uspoređeni s rezultatima simulacije za cijevi s inovativnim lamelama. Rezultati pokazuju povećanje iznosa Nu značajke od 20 % do 30 % za 2300 > Re > 12000 uz smanjenje mase izmjenjivačkih površina od 23,8 %.

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Compact Heat Exchangers

Cited by 1,177 publications

References 0 publications

Use of Hydraulic Models in Nuclear Reactor Design

Use of Hydraulic Models in Nuclear Reactor Design

Effectiveness-ntu computation with a mathematical model for cross-flow heat exchangers

Development of a new type of finned heat exchanger

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