Pressure drop in packed beds of spherical particles at ambient and elevated air temperatures

Pešić, Radojica; Kaludjerovic-Radoicic, Tatjana; Bošković‐Vragolović, Nevenka; Arsenijević, Zorana; Grbavčić, Željko

doi:10.2298/ciceq140618044p

Cited by 15 publications

(11 citation statements)

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“…For smooth spheres, it tends to over-predict f b in the high Re b range (Re b > 700) [14][15][16]; (b) if the bed particles are non-uniform in sizes, the Sauter mean diameter of particles should be used in the application of the Ergun equation; (c) when particle shape deviates significantly from a sphere, the Ergun equation tends to under-predict f b [17]; and (d) wall effects can be important when D b /d p < 10. When wall effects are important, the experimental data show deviation from the predictions of the Ergun equation [18]. can be important when < 10 ⁄…”

Section: Of 23mentioning

confidence: 99%

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Teach Second Law of Thermodynamics via Analysis of Flow through Packed Beds and Consolidated Porous Media

Pal

2019

Fluids

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The second law of thermodynamics is indispensable in engineering applications. It allows us to determine if a given process is feasible or not, and if the given process is feasible, how efficient or inefficient is the process. Thus, the second law plays a key role in the design and operation of engineering processes, such as steam power plants and refrigeration processes. Nevertheless students often find the second law and its applications most difficult to comprehend. The second law revolves around the concepts of entropy and entropy generation. The feasibility of a process and its efficiency are directly related to entropy generation in the process. As entropy generation occurs in all flow processes due to friction in fluids, fluid mechanics can be used as a tool to teach the second law of thermodynamics and related concepts to students. In this article, flow through packed beds and consolidated porous media is analyzed in terms of entropy generation. The link between entropy generation and mechanical energy dissipation is established in such flows in terms of the directly measurable quantities such as pressure drop. Equations are developed to predict the entropy generation rates in terms of superficial fluid velocity, porous medium characteristics, and fluid properties. The predictions of the proposed equations are presented and discussed. Factors affecting the rate of entropy generation in flow through packed beds and consolidated porous media are identified and explained.

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Section: Of 23mentioning

confidence: 99%

“…. When wall effects are important, the experimental data show deviation from the predictions of the Ergun equation [18]. Figure 5 shows the prediction of the packed bed friction factor as a function of packed bed Reynolds number using the Ergun equation, Equation (37).…”

Section: Of 23mentioning

confidence: 99%

Teach Second Law of Thermodynamics via Analysis of Flow through Packed Beds and Consolidated Porous Media

Pal

2019

Fluids

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“…A large number of correlations of the pressure drop in packed beds of spherical and non-spherical particles have been proposed. Among plenty of overviews of those correlations are those given by (Erdim, Ömer Akgiray, & Demir 2015;Kaludjerovic-Radoicic, Boskovic-Vragolovic, Garic-Grulovic, Djuris, & Grbavcic 2017;Pavlišič, Ceglar, Pohar, & Likozar 2018;Pesic, Kaludjerovic-Radoicic, Boskovic-Vragolovic, Arsenijevic, & Grbavcic 2015;Wang et al 2017). The most widely used equation for pressure drop in packed beds, the Ergun equation is valid for the incompressible flows through packed beds with neglected wall-to-bed effects and for Re' p numbers in the range 1.2<Re' p <4200.…”

Section: Introductionmentioning

confidence: 99%

“…However, research of pressure drop in packed beds at elevated temperatures is sparse (Luckos & Bunt 2011;Pesic et al 2015;Quintana-Solórzano, Che-Galicia, Trejo-Reyes, Armendáriz-Herrera, & Valente 2018). Luckos and Bunt (2011) found that the values of the pressure drop in a commercial gasifier, calculated according to the Ergun's equation (Ergun 1952), are not satisfactory because of the variation of temperature, composition and pressure of the gases flowing through the packed bed of coal particles in the investigated gasification process.…”

Section: Introductionmentioning

confidence: 99%

Momentum-heat-mass transfer analogy in gas-solid packed bed at elevated temperatures

Pešić,

Bošković-Vragolović,

Arsenijević

et al. 2022

J. eng. process. manag.

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The experimental values of the friction factor (fp) at ambient and elevated temperatures as well as of the heat transfer coefficient (hp) were used to establish the analogy between momentum and heat transfer in gas-solid packed beds of monosized spherical glass particles, as jH=fp/22 or jHε=fp/50. Also, the Chilton-Colburn type of momentum-mass transfer analogy was confirmed. These findings are valid for the range of the modified Reynolds number Re’p≈20-130. The experiments related to fp were performed by measuring the pressure drop across the packed bed of particles (0.58, 0.92, 1.04, 1.20, 1.94, 2.98, 3.91, and 4.91 mm diameters) heated to the desired temperature by hot air (temperatures from 20ºC to 350ºC). The range of gas superficial velocity was from 0.05 to 0.99 m/s, and the bed porosities were from 0.357 to 0.430. The experiments related to hp were performed by recording the temperatures of the cold aluminium test spheres (6, 12, and 20 mm in diameter) with embedded K-type (Ni/Al) thermocouples, immersed into the hot packed bed of particles (1.20, 1.94, and 2.98 mm diameters at temperatures from 100 to 300ºC) until the thermal equilibrium was reached. The superficial gas velocity and bed porosity varied from 0.30 to 0.79 m/s and from 0.392 to 0.406, respectively. A new correlation for the prediction of the heat transfer factor has been proposed in the form jHε=0.30(Re’p)-0.30. The analogies defined in this way leave the possibility of determining the value of the heat and mass transfer coefficients on the basis of the value of the friction factor, which is more common in the literature.

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“…There exists a variety of correlations for the prediction of the pressure drop in a fixed bed. A collection can be found by Pešić et al [1], according to which the pressure drop is influenced by the characteristic diameter, the diameter ratio of the packing elements, the filling height, the superficial velocity, the type of the fluid used, and the porosity (e) of the bed. In this context, the porosity is the void fraction of the packed bed.…”

Section: Introductionmentioning

confidence: 99%

Experimental Study on the Influence of Filling Method and Particle Material on the Packed‐Bed Porosity

Pottbäcker

Hinrichsen

2017

Chemie Ingenieur Technik

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The reliable prediction of the pressure drop of packed beds requires an accurate estimation of the packed-bed porosity as its error propagation multiplies the occurring errors by a factor of about four. The commonly used correlations to determine porosity depend only on the tube to particle diameter ratio. To improve accuracy, the influence of the filling method and of material properties, in particular surface roughness, density, and restitution coefficient are investigated for random packings of spheres in cylindrical confining walls. Furthermore, statistical methods are applied to identify interconnecting effects between these influencing parameters.

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Pressure drop in packed beds of spherical particles at ambient and elevated air temperatures

Cited by 15 publications

References 0 publications

Teach Second Law of Thermodynamics via Analysis of Flow through Packed Beds and Consolidated Porous Media

Teach Second Law of Thermodynamics via Analysis of Flow through Packed Beds and Consolidated Porous Media

Momentum-heat-mass transfer analogy in gas-solid packed bed at elevated temperatures

Experimental Study on the Influence of Filling Method and Particle Material on the Packed‐Bed Porosity

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