Wyniki wyszukiwania - BazTech

1

Long-term operation of pulse-jet filters for wood dust

Rogoziński Tomasz, Dembiński Czesław, Potok Zbigniew, Ockajova Alena, Kucera Martin, Kminiak Riichard

Annals of Warsaw University of Life Sciences - SGGW. Forestry and Wood Technology

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2023

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No. 121

61--65

EN

Long-term operation of pulse-jet filters for wood dust. The study specifies the value of flow resistance and separation efficiency of filter material during long-term use in pulse-jet filters for wood dust. The experiments were carried out for one type of material working in two different filtration installations in one furniture factory. The bags were obtained from the installations after working for 67, 133 and 272 days, respectively. All tests were performed on the pilot-scale test stand under identical filtration conditions. Studies have shown that long-term filter material use increases airflow resistance and improves filtration efficiency. The range of these changes depends on the operating conditions of the pulse-jet filters. The obtained results made it possible to determine the properties of the long-term use of filter materials in various filtration conditions.

PL

Długotrwała eksploatacja pulsacyjnych filtrów dla pyłu drzewnego. W pracy określono wartość oporów przepływu i skuteczność separacji materiału filtracyjnego podczas długotrwałego użytkowania w pulsacyjnych filtrach dla pyłu drzewnego. Eksperymenty przeprowadzono dla jednego rodzaju materiału pracującego w dwóch różnych instalacjach filtracyjnych w jednej fabryce mebli. Worki pozyskano z instalacji po odpowiednio 67, 133 i 272 dniach pracy. Wszystkie testy przeprowadzono na stanowisku pilotażowym w identycznych warunkach filtracji. Badania wykazały, że długotrwałe stosowanie materiału filtracyjnego zwiększa opory przepływu powietrza i poprawia skuteczność filtracji. Zakres tych zmian zależy od warunków pracy filtrów impulsowo-strumieniowych. Uzyskane wyniki pozwoliły na określenie właściwości przy długotrwałym użytkowaniu materiałów filtracyjnych w różnych warunkach filtracji.

2

Pressure drops during the flow of solutions of cocamidopropyl betaine and cocamide DEA mixtures with the addition of ethylene glycol

Różańska Sylwia, Różański Jacek, Wagner Patrycja, Warmbier Ewelina

Polish Journal of Chemical Technology

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2022

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Vol. 24, nr 4

67--71

EN

The paper presents the results of experimental studies on pressure drops during the flow of cocamidopropyl betaine (CAPB) and DEA cocamide solutions with the addition of ethylene glycol. The degree of drag reduction during the flow of the CAPB/DEA aqueous solution and with the 10% addition of ethylene glycol was similar. A significant reduction in pressure drops was also observed at the 20% concentration of ethylene glycol. However, the increase in the concentration of ethylene glycol resulted in the reduction of flow resistance at higher temperatures. The resistance of the micellar microstructure of CAPB/DEA solutions to mechanical degradation depends strongly on the pH level. Significant changes in flow properties were observed when the initial pH was alkaline. The solution with initial pH close to neutral was stable over time, though reduced resistance to degradation with time was also observed.

3

Requirement of pressure relief dampers for clean rooms

Hrnková Bronislava, Hečko Dávid, Kapjor Andrej, Mičko Pavol, Vantúch Martin

Structure and Environment

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2021

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Vol. 13, no. 2

55--58

EN

The clean room is designed and used to minimize the entry, generation and deposition of pollutants. Proper flow control is an important factor in determining the efficiency of clean rooms. It is important that the air stream entrains from the space all the particles that are released when people move, but also from equipment and various materials. Therefore, in the following article we will deal with the need for pressure dampers in clean rooms.

PL

Pomieszczenie czyste jest zaprojektowane i wykorzystywane w taki sposób, aby zminimalizować wnikanie, generowanie i osadzanie się zanieczyszczeń. Właściwa kontrola przepływu powietrza jest istotnym czynnikiem określającym efektywność pomieszczeń czystych. Ważne jest, żeby strumień powietrza porywał z przestrzeni wszystkie cząstki, które są uwalniane podczas ruchu ludzi, ale także ze sprzętu i różnych materiałów. W związku z powyższym w niniejszym artykule zajmiemy się potrzebą stosowania klap nadciśnieniowych w pomieszczeniach czystych.

4

Analiza numeryczna spadku ciśnienia w zaworze maksymalnym układu smarowania pojazdów spalinowych

Mazur Klaudia

Journal of TransLogistics

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2021

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Vol. 7, nr 1

85--98

PL

W poniższej pracy przedstawiono analizę przepływu oleju przez zawór przelewowy typu UDZB firmy PONAR Wadowice wykorzystywany w układach smarowania. Ma to na celu przedstawienie zachodzących zjawisk podczas zmiany wielkości szczeliny w zaworze. W pracy zawarte są informacje dotyczące spadku ciśnienia – czym jest spowodowany oraz jakie mogą być jego skutki.

EN

The paper below presents an analysis of the oil flow through the PONAR Wadowice UDZB overflow valve used in lubrication systems. Its aim is to present the phenomena occurring when changing the size of the gap in the valve. The paper contains information on the pressure drop – why does it happen and what its effects may be.

5

Problems of selecting filter partition in passenger car engine intake air filters

Dziubak Tadeusz, Bąkała Leszek

Combustion Engines

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2021

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R. 60, nr 2

44--58

EN

The aim of this study was to verify the criteria for selecting pleated filter partitions used in passenger car engine filters. The paper presents the problem of optimizing pleated air filters in the direction of minimizing pressure drop, which is the source of engine energy losses. Two criteria for selection of a paper filter partition for specific operating conditions of the filter and the engine are presented: criterion of permissible separation speed and criterion of permissible pressure drop. The actual filtration area of 44 paper pleated filter elements used in passenger cars and the air stream flowing through the filter were determined, which made it possible to calculate separation speed. In 62% of the analyzed filter inserts, the calculated separation speeds are within the speed range recommended by the constructors, ʋFmax = 0.06-0.12 m/s. Exceeding permissible separation speed ʋFmax = 0.12 m/s was found mainly in supercharged engines. Negative effects of engine operation with an air filter with too small separation area are presented, in the form of increased pressure drop and energy loss of the engine as well as shorter car mileage to reach permissible pressure drop.

6

Struktura roztworów polimerowo-micelarnych

Malcher Tadeusz

Przemysł Chemiczny

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2020

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T. 99, nr 9

1342--1343

PL

Roztwory polimerowo-micelarne swoje właściwości zmniejszania oporów przepływu zawdzięczają strukturze wewnętrznej. Struktura ta powstaje najczęściej podczas zmieszania roztworu polimerowego z roztworem zawierającym środek powierzchniowo czynny.

EN

Fundamentals and review with 24 refs.

7

Rheological behavior of fly ash suspension with additive for hydraulic conveyance

Kumar K.

International Journal of Applied Mechanics and Engineering

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2020

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Vol. 25, no. 2

202--210

EN

In the present work, rheological behaviour of a fine particulate fly ash slurry suspension is studied with and without addition of an additive. Rheological experiments are performed for the range of shear rate from 50 to 200 s1.Sodium sulfate is used as an additive in the fraction of 0.2, 0.4 and 0.6% (by weight). Addition of sodium sulfate to the fly ash slurry suspension leads to an improvement of its rheological characteristics. A reduction in relative viscosity and pressure drop is more pronounced with the addition of sodium sulfate in proportion of 0.4%, while marginal with 0.2 and 0.6% (by weight). The analysis reveals that the fly ash suspension has a potential to for being transported in a slurry pipeline with higher concentration and minimum energy consumption.

8

Pressure drop reduction in fluid flows with a polymer solution

Edomwonyi-Otu Lawrence Chukwuka

Engineering Transactions

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2020

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Vol. 68, iss. 4

371--383

EN

This work is targeted at making available some data to enhance the development of better predictive models for drag reduction (DR) in two-phase flows. Oil-water flows studies were carried out by using a horizontal acrylic pipe (14 mm ID) with tap water and a middle distillate oil the flowing liquids. A hydrolysed polyacrylamide served as the polymer in the water phase. Polyethylene oxide (PEO) with two different molecular weights was equally investigated. At an optimal polymer concentration of 20 ppm, drag was lowered as Reynolds number increased. While drag reduction was effectively described by models, it increased with polymer weight.

9

Model of forced turbulence for pulsing flow

Dmytriv Vasyl

Diagnostyka

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2020

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Vol. 21, No. 1

89--96

EN

The article deals with fluid motion along an infinite hose. Taking into consideration the Stokes equation, the tangential friction stresses according to Newton and the Reynolds equation, the differential equation of the velocity change in radius is developed taking into account the pulsating component of the friction forces in the turbulent flow. Turbulence is defined as the impulse component of a flow, characterized by a pressure drop along a dynamic length of flow, a frequency response, and an oscillation amplitude of the pressure drop of pulse (which is given by the time equation of the oscillation). The velocity distribution along the radius of the hose in the time interval of one second was modelled for pressure drops in the range from 6000 to 18000 Pa and the amount of transported medium in the range from 1.667·10-5 to 6.667·10-5 m3 , which corresponded to the length of pulse plug. The dynamic viscosity of the medium (milk) of 1.79 · 10-3 Pa·s and its density of 10273 N·s2 /m4 were accounted at the simulation. The developed analytical dependence of the velocity of the forced turbulence of the pulsating flow allows to calculate the absolute value of the velocity at a given point of crosssection of the pipeline, and characterizes the physical process of flow of Newtonian fluids and gases in the pipeline.

10

Study on the Relationship Between Structure Parameters and Filtration Performance of Polypropylene Meltblown Nonwovens

Xiao Yuanxiang, Sakib Nazmus, Yue Zhonghua, Wang Yan, Cheng Si, You Jianmin, Militky Jiri, Venkataraman Mohanapriya, Zhu Guocheng

Autex Research Journal

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2020

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Vol. 20, no. 4

366--371

EN

In this study, polypropylene meltblown nonwoven fabrics with different structure parameters such as fiber diameter, pore size, and areal density were prepared by the industrial production line. The morphology of meltblown nonwoven fibers was evaluated by using scanning electron microscope, and the diameter of fibers was analyzed by using image-pro plus software from at least 200 measurements. The pore size of nonwoven fabric was characterized by a CFP-1500AE type pore size analyzer. The filtration efficiency and pressure drop were evaluated by TSI8130 automatic filter. The results showed that the pressure drop of nonwoven fabrics decreased with the increase in pore size; the filtration efficiency and the pressure drop had a positive correlation with the areal density. However, when the areal density is in the range of 27–29 g/m2, both filtration efficiency and pressure drop decreased with the increase of areal density; when the areal density was kept constant, the filtration efficiency decreased as the pore size decreased; when the pore size of the meltblown nonwoven fabric is less than 17 μm, the filtration efficiency increased as the pore diameter decreased; when the pore diameter of the nonwoven fabric is larger than 17 μm. In a wide range, the pressure drop decreased as the fiber diameter decreased.

11

Numerical investigation and sensitivity analysis of turbulent heat transfer and pressure drop of Al2O3/H2O nanofluid in straight pipe using response surface methodology

Fadodun Olatomide G., Amosun Adebimpe A., Salau Ayodeji O., Olaloye David O., Ogundeji Johnson A., Ibitoye Francis I., Balogun Fatai A.

Archives of Thermodynamics

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2020

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Vol. 41, no 1

3--30

EN

In this paper, investigation of the effect of Reynolds number, nanoparticle volume ratio, nanoparticle diameter and entrance temperature on the convective heat transfer and pressure drop of Al2O3/H2O nanofluid in turbulent flow through a straight pipe was carried out. The study employed a computational fluid dynamic approach using single-phase model and response surface methodology for the design of experiment. The Reynolds average Navier-Stokes equations and energy equation were solved using k-ε turbulent model. The central composite design method was used for the response-surface-methodology. Based on the number of variables and levels, the condition of 30 runs was defined and 30 simulations were performed. New models to evaluate the mean Nusselt number and pressure drop were obtained. Also, the result showed that all the four input variables are statistically significant to the pressure drop while three out of them are significant to the Nusslet number. Furthermore, sensitivity analysis carried out showed that the Reynolds number and volume fraction have a positive sensitivity to both the mean Nusselt number, and pressure drop, while the entrance temperature has negative sensitivities to both.

12

Innovative method for heat transfer enhancement through shell and coil side fluid flow in shell and helical coil heat exchanger

Kumar Rajesh, Chandra Prakash, Prabhansu

Archives of Thermodynamics

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2020

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Vol. 41, no 2

239--256

EN

The effect of shell side and coil side volume flow rate on overall heat transfer coefficient, effectiveness, pressure drop and exergy loss of shell and helical coil heat exchanger were studied experimentally under steady state conditions. The working fluid, i.e., water was allowed to flow at three different flow rates of 1, 2, and 3 l/min on shell side (cold water) and at 1, 1.5, 2, 2.5, and 3 l/min on coil side (hot water) for each shell side flow rate at the temperatures of 298±0.4 K and 323±0.4 K, respectively. The results found that the overall heat transfer coefficient increased with increasing both shell side and coil side volume flow rates. The inner Nusselt number significantly increased with the coil side Dean number.

13

Features of hydrates transportation in a fluid flow

Vozniak Lidiia V., Kryvenko Galyna M.

Journal of New Technologies in Environmental Science

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2019

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Vol. 3, nr 2

84--88

EN

Significant deposits of natural gas are in a gas-hydrated state. One of the options for a possible solution is the transport of hydrates in a fluid flow. The stability of crystalline hydrates, namely, their presence in the solid state, affects both temperature and pressure. The influence of the concentration of solid particles on the reduction or increase of the friction factor is shown, which leads to a decrease or increase in pressure drop during the flow of liquid with solid admixtures. The analytical dependences of the friction factor from the Reynolds number on a certain concentration of solid admixtures in a liquid are proposed A plot of the dependence of the friction factor from the Reynolds number on a certain concentration of rubber crumb and different granulometric composition was constructed.

14

Optimization of compressed heat exchanger efficiency by using genetic algorithm

Ghorbani M., Ranjbar S. F.

International Journal of Applied Mechanics and Engineering

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2019

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Vol. 24, no. 2

461--472

EN

Due to the application of coil-shaped coils in a compressed gas flow exchanger and water pipe flow in airconditioner devices, air conditioning and refrigeration systems, both industrial and domestic, need to be optimized to improve exchange capacity of heat exchangers by reducing the pressure drop. Today, due to the reduction of fossil fuel resources and the importance of optimal use of resources, optimization of thermal, mechanical and electrical devices has gained particular importance. Compressed heat exchangers are the devices used in industries, especially oil and petrochemical ones, as well as in power plants. So, in this paper we try to optimize compressed heat exchangers. Variables of the functions or state-of-the-machine parameters are optimized in compressed heat exchangers to achieve maximum thermal efficiency. To do this, it is necessary to provide equations and functions of the compressed heat exchanger relative to the functional variables and then to formulate the parameter for the gas pressure drop of the gas flow through the blades and the heat exchange surface in relation to the heat duty. The heat transfer rate to the gas-side pressure drop is maximized by solving the binary equation system in the genetic algorithm. The results show that using optimization, the heat capacity and the efficiency of the heat exchanger improved by 15% and the pressure drop along the path significantly decreases.

15

Properties of material with nanofiber layer used for filtering the inlet air of internal combustion engines

Dziubak Tadeusz

Combustion Engines

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2019

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R. 58, nr 2

66--75

EN

Nanofiber properties, and the possibilities of their application in industry, including the production of car air intake filtration materials for vehicle engines are discussed. The attention is paid to the low efficiency of standard filtration materials based on cellulose in the range of dust grains below 5 μm. The properties of filtration materials with nanofibers addition are described. The conditions, and methodology of material filter paper tests at the station with particle counter were developed. Studies on the filtration characteristics, such as: efficiency, accuracy, as well as pressure drop of filtration materials differing in structure were made: standard paper, cellulose, and these materials with the addition of nanofibers. These are commonly used filter materials for filter inserts production of car air intake systems. Test results show significantly higher values of the efficiency, and filtration accuracy of materials with nanofiber layer addition of dust grains below 5 μm in comparison with standard filter paper. It was found that there are 16 μm dust grains in the air flow behind the insert made out of cellulose, which may be the reason for the accelerated wear of the engine's "piston-piston ring-cylinder" association. Lower values of dust mass loading coefficient km for filtration materials with the addition of nanofiber layer, in relation to standard filter paper were observed.

16

Badanie oporów przepływu podczas skraplania czynników chłodniczych w minikanałach pionowych

Bohdal Tadeusz, Kruzel Marcin, Sikora Małgorzata

Chłodnictwo : organ Naczelnej Organizacji Technicznej

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2019

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R. 54, nr 1

14--19

PL

Praca zawiera opis eksperymentalnych badań przepływowych procesu skraplania wysokociśnieniowych czynników chłodniczych w pionowych minikanałach rurowych. Zbadano wpływ gęstości strumienia masy, stopnia suchości pary i średnicy wewnętrznej minikanału na proces skraplania. W tych samych warunkach skraplano czynniki R404A, R407C, R410A. Opracowanie obejmuje również podsumowanie danych uzyskanych podczas procesu skraplania wszystkich trzech badanych czynników chłodniczych. Wyniki badań eksperymentalnych porównano z wynikami modelowania teoretycznego według zależności opracowanych przez innych autorów. Zgodność danych modelowania z wynikami eksperymentu została uznana za niezadowalającą. Na podstawie wyników danych eksperymentalnych uzyskano model służący do predykcji spadków ciśnienia dla niskich strumieni ciepła (q do 5000 W/m2).

EN

The paper consists a description of experimental flow tests of high- -pressure refrigerants condensation process in vertical pipe minichannels. The influence of mass flux density, vapour quality and minichannel’s internal diameter on the condensation process was investigated. Under the same conditions, R404A, R407C, R410A refrigerants were condensed. The work also includes a summary of data obtained during the condensation process of all three tested refrigerants. The results of experimental studies were compared with the results of theoretical modeling according to correlations developed by other authors. The compliance of the modeling data with the results of the experiment was considered unsatisfactory. Based on the results of experimental data, a pressure drop prediction model was obtained for low heat fluxes (q up to 5000 W/m2).

17

Heat transfer in helical coil heat exchanger:An experimental parametric study

Kowalski Krzysztof, Downarowicz Dorota

Chemical and Process Engineering

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2019

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Vol. 40, nr 1

101–-114

EN

Helical coil heat exchangers are widely used in a variety of industry applications such as refrigerationsystems, process plants and heat recovery. In this study, the effect of Reynolds number and theoperating temperature on heat transfer coefficients and pressure drop for laminar flow conditions wasinvestigated. Experiments were carried out in a shell and tube heat exchanger with a copper coiledpipe (4 mm ID, length of 1.7 m and coil pitch of 7.5 mm) in the temperature range from 243 to 273 K.Air – propan-2-ol vapor mixture and coolant (methylsilicone oil) flowed inside and around the coil,respectively. The fluid flow in the shell-side was kept constant, while in the coil it was varied from 6.6to 26.6 m/s (the Reynolds number below the critical value of 7600). Results showed that the helicalpipe provided higher heat transfer performance than a straight pipe with the same dimensions. Theconvective coefficients were determined using the Wilson method. The values for the coiled pipe werein the range of 3–40 W/m2·K. They increased with increasing the gas flow rate and decreasing thecoolant temperature.

18

Thermal modification of wood by the method of thermo-mechanical dehydration with pressure drop

Zashchepkina N.M., Prokopovich O.V., Makarenko D.S.

Annals of Warsaw University of Life Sciences - SGGW. Forestry and Wood Technology

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2019

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No. 106

128--133

EN

Thermal Modification of Wood by the Method of Thermo-Mechanical Dehydration with Pressure Drop. The results of experimental research of thermal wood processing by the method of high temperature drying with pressure drop are presented. Drying was carried out cyclically by heating the material under pressure to the temperature 100-140 oC followed by pressure drop. After that the temperature was raised up 160-210 oC and the samples were processed briefly in those conditions. This treatment is shown to be effective for largesized wood.

PL

Termiczna modyfikacja drewna metodą termo-mechanicznego suszenia z redukcją ciśnienia. Przedstawiono wyniki badań eksperymentalnych obróbki termicznej drewna metodą suszenia wysokotemperaturowego ze spadkiem ciśnienia. Suszenie prowadzono cyklicznie poprzez ogrzewanie materiału pod ciśnieniem do temperatury 100- 140 oC, a następnie redukcji ciśnienia. Kolejno temperaturę podwyższano do 160-210 oC i realizowano obróbkę termiczną. Modyfikacja tego typu okazała się szczególnie skuteczna w przypadku elementów drewnianych o dużych rozmiarach.

19

Flows of Sisko Fluid Through Symmetrically Curved Capillary Fissures and Tubes

Walicka A., Jurczak P., Falicki J.

Machine Dynamics Research

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2018

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Vol. 42, No. 3

27--54

EN

This paper presents a general analytical method for deriving mathematical relationships between pressure losses and the volumetric ﬂow rate for laminar ﬂows of a Sisko ﬂuid. In this paper, only the laminar ﬂow of Sisko type ﬂuids is considered. It was demonstrated that the method can be used to ﬁnd solutions for other pseudoplastic ﬂuids and for different hapes of fissures and tubes. It can also be a good basis for numerical integration when analytical expressions are hard to obtain due to mathematical complexities. As an example, the following cases of convergent-divergent or divergent-convergent ﬁssures and tubes, namely: parabolic, hyperbolic, hyperbolic cosine and cosine curve were considered. For each example, the formulae for pressure losses, volumetric ﬂow rate and ﬂow velocity were obtained. The most general forms of these formulas can be obtained by introducing hindrance factors.

20

Experimental and numerical study of the heat transfer and pressure drop in triangular chevron channels

Dolatabadi H., Aghdam A. H.

Journal of Theoretical and Applied Mechanics

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2018

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Vol. 56 nr 3

751--763

EN

Experimental and Numerical studies were carried out on turbulent heat transfer and friction factor loss through a triangular chevron channel. For uniform wall heat flux equal 1350 (W/m²) using air as a working fluid. Reynolds number varied from 3000 to 10000, phase shifted at the range of 0≤ϕ≤180, with variation distance between chevron surfaces (5 ≤ D ≤ 35 mm). Nu increased and TEF decreased in increasing of Re. The TEF and Nu increased with closing to channel phase shift angle 90˚, the best performance was noticed on phase shift, ϕ=90º. At the end of this paper effect of distance between chevron surfaces presented, The TEF and Nu increased with decreasing to channel distance and the best performance was noticed on closing to D=5(mm).