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Influence of nozzle geometry on fluid flow parameters

Penkov I., Aleksandrov D.

International Journal of Applied Mechanics and Engineering

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2020

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Vol. 25, no. 4

214--222

EN

The article discusses ways for optimization of a standard nozzle cup design to achieve a narrower paint flow. The analysis of a standard nozzle cup shows that distribution of air pressure is critically uneven both along the nozzle axis and in the radial direction. A decrease in pressure is about 45% at the distance of 2 mm from the front surface of the nozzle cup. Air pressure decreases about 40% at the distance of 2 mm from the nozzle axis in the radial direction. Air velocity decreases about 52% at the distance of 4 mm from nozzle surface but then the velocity stabilizes and decreases is about 59% at the distance of 10 mm from the nozzle surface in comparison to its magnitude on the nozzle surface. Six extra holes and a circular rim were added to the standard nozzle cup to obtain paint stream as narrow as possible. Also was modified inner surface of the nuzzle cup. Totally, four different components were analysed. The results show that with increasing the nozzle cone by fifteen or more degrees, the pressure distribution decreases. Most optimal solution has six small holes around the nozzle hole and a small rim covering all holes. In this case, pressure decreases only 3% in the axial direction and 4% in the radial direction at the distance of 2 mmfrom the front surface of the nozzle. Distribution of air velocity is still significant but its magnitude is about 35% ... 45% less than at the standard nozzle cup.

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Machining of microholes in Ti-6Al-4V by hybrid micro electrical discharge machining to improve process parameters and flushing properties

Mugilan T., Aezhisai Vallavi M. S., Santhosh S., Sugumar D., Christopher Ezhil Singh S.

Bulletin of the Polish Academy of Sciences. Technical Sciences

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2020

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Vol. 68, nr 3

565--573

EN

In this research work, the Ti-6Al-4V material was used for the investigation of machining parameters by means of hybrid micro electrical discharge machining to improve the machining process and reduce the negative effects of debris accumulation in the drilled hole. L9 orthogonal array was used in the Taguchi based grey relational analysis to optimize the parameters such as material removal rate and diametrical accuracy of the machining process for Ti-6Al-4V. This work encompasses the design, development, and calibration of the work piece vibration platform and experimental analysis of the process parameters by means of the hybrid micro electrical discharge machining process. The maximum material removal rate and minimum surface roughness was observed at the current value of 2.5 A, pulse on time is 2 μs and pulse off time is 14.5 μs. The maximum material removal rate was observed for the increase in pulse on time with 14.4 μs and 4 A current level. The diametrical accuracy of the microholes was increased while increasing the pulse off time and decreasing the pulse on time. The fluid flow simulation has been conducted to find out the pressure drop and to know the velocity of the flow inside the hole for the effective flushing of the debris during machining.

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Symulacja przepływu płynu w kadzi wirowej o wielopunktowym napełnianiu

Sterczyńska M., Jakubowski M.

Inżynieria Rolnicza

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2012

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R. 16, nr 3

227-235

PL

Praca prezentuje porównanie wyników uzyskanych dla modelu symulacyjnego CFD (Coputational Fluid Dynamcs) kadzi wirowej o napełnianiu jednostronnym (klasycznym) i zwielokrotnionym po obwodzie. Przedmiotem analizy było określenie wpływu zastosowania napełniania z wykorzystaniem czerech otworów rozmieszczonych symetrycznie na płaszczyźnie płaszcza zbiornika kadzi wirowej na występowanie przepływ wtórnego odpowiedzialnego za formowanie się stożka osadu gorącego. Analiza czasów formowania oraz wartości prędkości maksymalnej przepływu wtórnego który jest odpowiedzialny za powstawania specyficznego kształtu stożka osadu wykazała zróżnicowanie wyników w zależności od wariantu napełniania. W odniesieniu do klasycznego napełniania korzystniejsze warunki (skrócenie czasu powstawania przepływu formującego stożek osadu oraz wyższą wartość prędkości) uzyskano przy napełnianiu wielostronnym.

EN

The paper presents the comparison of simulation results obtained for the Computational Fluid Dynamics CFD) model of the whirlpool tank of one-sided inflow (classic) and multiplied by the circumference. The subject of the analysis was to determine the effect of using four inlets placed symmetrically on a whirlpool plane of the tank on the occurrence of the secondary flow which is responsible for the formation of the hot trub cone. Analysis of the formation time and the speed of the secondary flow which is responsible for the formation of the specific shape of the cone of sediment results showed differences depending on the variant of the filling. With respect to the classical filling better conditions (shorter cone formation forming sediment flow and higher speed) achieved during the filling multilateral.