Wyniki wyszukiwania - BazTech

1

3D simulation of incompressible flow around a rotating turbulator: Effect of rotational and direction speed

Zoubai Elhadi, Laidoudi Houssem, Tlanbout Ismail, Makinde Oluwole Daniel

Archives of Thermodynamics

|

2023

|

Vol. 44, no 2

139--157

EN

This paper presents new results for the dynamic behaviour of fluid around a rotating turbulator in a channel. The turbulator has a propeller form which is placed inside a flat channel. The research was carried out using 3D numerical simulation. The rationale of the experiment was as follows: we put a propeller-turbulator inside a flat channel, and then we insert a water flow inside the channel. The turbulator rotates at a constant and uniform speed. The main points studied here are the effect of the presence of turbulator and its rotational direction on the flow behaviour behind the turbulator. The results showed that the behaviour of flow behind the turbulator is mainly related to the direction of turbulator rotating. Also, the studied parameters affect coefficients of drag force and power number. For example, when the turbulator rotates in the positive direction, the drag coefficient decreases in terms of rotational speed of the turbulator, while the drag coefficient increases in terms of rotational speed when the turbulator rotates in the negative direction.

2

Wpływ zawirowania strugi spalin na obniżenie emisji pyłów oraz podniesienie sprawności cieplnej kotła peletowego

Ciupek B.

Ciepłownictwo, Ogrzewnictwo, Wentylacja

|

2018

|

T. 49, nr 8

333--338

PL

W artykule przedstawiono analizę wpływu zawirowania strugi spalin odlotowych kotła grzewczego na obniżenie emisji pyłów oraz podniesienie sprawności cieplnej urządzenia. Badany obiekt spełniał warunki cieplno-emisyjne w odniesieniu do kotłów wykonanych zgodnie z Rozporządzeniem Komisji (UE) 2015/1189 dotyczących ekoprojektu dla kotłów na paliwa stałe oraz normy PN-EN 303-5:2012. Kocioł był wyposażony przez producenta w palnik na paliwo stałe typu pelet drzewny. W trakcie badań praca kotła była sterowana przez mikroprocesorowy regulator temperatury. Celem badań było sprawdzenie czy zastosowanie turbulatorów spalin w częściach konwekcyjnych kotła obniży stężenie cząstek stałych oraz zwiększy sprawność cieplną urządzenia. W artykule opisano metodykę badań oraz analizę otrzymanych wyników. Skutkiem przeprowadzonych badań jest zestawienie średnich wartości emisji pyłów oraz otrzymanej mocy cieplnej w zależności od liczby zastosowanych turbulatorów. Wyniki badań stanowią przesłankę do dalszych prac badawczych w aspekcie wpływu zawirowania strugi spalin na obniżenie stężenia pyłów i podniesienia sprawności cieplnej kotłów na paliwa stałe.

EN

The article presents the analysis of the influence of turbulence in the stream of waste gas from a boiler to reduce dust emissions and increase the thermal efficiency of the device. The research facility met the heat and emission conditions for boilers made in accordance with the EU Commission Regulation 2015/1189 regarding the ecodesign for solid fuel boilers and EN 303-5:2012. The boiler was supplied with a wood pellet burner dedicated from the manufacturer. During the tests, boiler operation was controlled by a microprocessor temperature controller. The aim of the research was to check if using turbulators in the boiler’s convection parts a reduction of particulate matter emission would be achieved and the thermal efficiency of the device would increase. The article describes the research methodology used and the analysis of the results obtained. The effect of the conducted tests is a comparison of average dust emission values and thermal power received depending on the number of turbulators used. The test results are a prerequisite for further research work in terms of the impact of turbulence in the exhaust stream on reducing dust emissions and increasing the thermal efficiency of solid fuel boilers.

3

Numerical analysis of heat transfer through a circular pipe with porous-ring turbulators

Akansu S., Ceper B., Yapici H.

Chemical and Process Engineering

|

2008

|

Vol. 29, z. 4

1053-1070

EN

A numerical study has been carried out of heat transfer enhancement and flow characteristics through artificial porous materials in the form of ring turbulators on heated wall of a circular pipe for turbulent flow (Reynolds number range 16 000.64 000). In the study, uniform heat flux of 2500 W/m2 from a circular pipe wall surface has been assumed. A significant enhancement of heat transfer in the porous-ring turbulators is observed compared with that in a smooth surface. Four various shapes of porous- ring turbulators (0 (solid), 0.2, 0.4 and 1 (smooth circular pipe) porosity) have been examined using the RNG k.. turbulence model, and compared based on heat transfer enhancement and friction characteristics. Heat transfer decreases with increasing porosity. Using porous-ring turbulators in the pipe gives an increase in the Nusselt number and heat transfer enhancement. Therefore, such turbulators may be used in heat exchangers to increase heat transfer and energy saving.