Wyniki wyszukiwania - BazTech

1

Experimental Study on the Diverse Output Performance of a Firearm Firing-Ignition System

Li Bo, Wei Yanzhong, Xin Changfan, Wei Zhifang, Shi Yukun

Central European Journal of Energetic Materials

|

2023

|

Vol. 20, no. 4

455--477

EN

The firearm firing-ignition system performs firing and ignites a bullet propellant to produce diverse outputs. The objectives of this study were to extract various performance parameters characterizing the firearm firing-ignition system and to study the system output performance. The firing pins, primers, and cartridge cases were used as test objects, and a method for testing the diverse output performance of the firearm firing-ignition system is proposed based on the real assembly relationship of firearms. The pressure output patterns and flame characteristics were analyzed under different operating conditions and ambient temperatures. With increasing firing energy, the pressure start time and peak arrival time of the firearm firing-ignition system output decreased, whereas the length of the flame output generally increased. The flame duration was positively correlated with the firing energy. The development of the shape and temperature of the flame output could be categorized into four stages, where the maximum flame length of 60-70 mm occurred during the third stage and the highest temperature of 1218 ℃ was reached during the second stage. This study resolves the problem that the firearm firing–ignition system has a variety of outputs but only a single characterization parameter (the primer sensitivity) and engineering practice fails to quantitatively evaluate the system output performance.

2

Measurement of flame temperature and soot amount for effective NOx and PM reduction in a heavy duty diesel engine

Aoyagi Yuzo

Combustion Engines

|

2019

|

R. 58, nr 4

32--39

EN

To reduce exhaust NOx and smoke, it is important to measure flame temperature and soot amount in combustion chamber. In diesel combustion it is effective to use the two-color method for the measurement of the flame temperature and KL factor, which is related with soot concentration. The diesel flame was directly and continuously observed from the combustion chamber at running engine condition by using a bore scope and a high-speed video camera. The experimental single cylinder engine has 2.0-liter displacement and has the ability with up to five times of the boost pressure than the naturally aspirated engine by external super-charger. The devices of High Boost, Wide Range and High EGR rate at keeping a relatively high excess air ratio were installed in this research engine in order to reduce exhaust NOx emission without smoke deterioration from diesel engines. The video camera nac GX-1 was used in this study. From observed data under the changing EGR rates, the flame temperature and KL factor were obtained by the software of two-color method analysis. The diesel combustion processes are understood well by analyzing high-speed movies of the diesel flame motion and its temperature. The NOx and smoke are mutually related to maximum flame temperature and also it is possible to reduce simultaneously both NOx and soot emissions by high EGR rate in a single cylinder diesel engine.

3

Optical identification of the combustion of air-fuel mixture surrounded by non-combustible gas in a rapid compression machine

Cieślik W., Pielecha I., Wisłocki K.

Archivum Combustionis

|

2017

|

Vol. 37 nr 2

93--106

EN

The influence of non-combustible gas injection on combustion rates in an engine cylinder with centrally positioned ignition point has been discussed. The flame temperature distribution and its changes were taken into account in this research. The analysis of the influence of exhaust gas content in the cylinder on the combustion process has been based on the interpretation of high speed camera images for the period from the ignition start to full flame coverage of the combustion chamber. Authors performed a comparative analysis of the combustion process thermodynamic parameters based on the obtained characteristics. In order to demonstrate the charge stratification influence and the proportion of flue gas in the cylinder, a flame propagation analysis was performed through high frequency image sampling and using the flame temperature distribution in the combustion volume. The two-color method was used for determining this temperature. A flame temperature distribution example at selected combustion process stages was presented as well as for the entire combustion process. A significant reduction in the area covered by the flame was shown to be the result of an increase in the flue gas proportion in the cylinder. The flame area reduction was found to be 46% when using a 25% EGR share, while with an EGR contribution of 40%, the flame area was decreased by 78%. The flame covered area reduction was the result of "fencing" of the flame from the cylinder walls by an exhaust gas layer. According to changes in the flame area, the largest share of high temperatures, in the range 1800-2000 K, has also decreased from around 19% to 23%.

4

Investigation on effect of air velocity in turbulent non-premixed flames

Namazian Z., Hashemi H., Namazian F.

Archive of Mechanical Engineering

|

2016

|

Vol. LXIII, nr 3

355--366

EN

In this study, the turbulent non-premixed methane-air flame is simulated to determine the effect of air velocity on the length of flame, temperature distribution and mole fraction of species. The computational fluid dynamics (CFD) technique is used to perform this simulation. To solve the turbulence flow, k-ε model is used. In contrast to the previous works, in this study, in each one of simulations the properties of materials are taken variable and then the results are compared. The results show that at a certain flow rate of fuel, by increasing the air velocity, similar to when the properties are constant, the width of the flame becomes thinner and the maximum temperature is higher; the penetration of oxygen into the fuel as well as fuel consumption is also increased. It is noteworthy that most of the pollutants produced are NOx, which are strongly temperature dependent. The amount of these pollutants rises when the temperature is increased. As a solution, decreasing the air velocity can decrease the amount of these pollutants. Finally, comparing the result of this study and the other work, which considers constant properties, shows that the variable properties assumption leads to obtaining more exact solution but the trends of both results are similar.

PL

W pracy przeprowadzono symulację turbulentnego płomienia metanowo-powietrznego bez mieszania wstępnego w celu wyznaczenia wpływu szybkości powietrza na długość płomienia, rozkład temperatur oraz ułamek molowy składników spalin. Do przeprowadzenia symulacji wykorzystano technikę obliczeniowej dynamiki płynów (CFD). Przy rozwiązaniu przepływu turbulentnego zastosowano model k-ε. W przeciwieństwie do poprzednich prac, w prezentowanym studium założono zmienne właściwości materiałów w każdej z symulacji, a wyniki symulacji porównywano. Rezultaty badań pokazują, że przy określonej prędkości przepływu paliwa, przy wzroście szybkości powietrza uzyskuje się cieńszy płomień, o wyższej temperaturze, podobnie jak w przypadku gdy zakłada się stałe właściwości. Wzrasta przy tym penetracja tlenu do płomienia, a także zużycie paliwa. Warto zauważyć, że większość powstających szkodliwych substancji to tlenki azotu (NOx), silnie zależne od temperatury. Zawartość tych zanieczyszczeń rośnie ze wzrostem temperatury. Rozwiązaniem jest zmniejszenie szybkości powietrza, co może zmniejszyć zawartość zanieczyszczeń. Ostatecznie, porównując wyniki tego studium i poprzedniej pracy gdzie założono stałe właściwości materiałów, pokazano, że założenie zmiennych właściwości prowadzi do otrzymania dokładniejszych rozwiązań, niemniej, wyniki wykazują w obydwu przypadkach ten sam trend.

5

The features of flame temperature measurement

Herasymenko V., Seheda O., Stadnyk B.

Zeszyty Naukowe Politechniki Rzeszowskiej. Elektrotechnika

|

2015

|

z. 34 [292], nr 3

81--85

EN

The flame temperature measurement gives the understanding of combustion processes and is important for the temperature control systems. In this paper the review and analyze of the methods of flame temperature measurement are represented. Each of them is effective under certain condition. Nowadays the method of Raman-scattering is promising in this field. It pretends to avoid some of the errors in other existing techniques.

PL

Pomiar temperatury płomienia pozwala zrozumieć procesy spalania i jest ważnym dla systemów kontroli temperatury. W artykule przedstawiona jest analiza metod pomiaru temperatury płomienia. Każda z nich jest skuteczna przy spełnieniu pewnych warunków. W tej dziedzinie metoda rozpraszania ramanowskiego jest obecnie obiecująca. Wspomniana metoda pozwala uniknąć niektórych błędów charakterystycznych dla innych technik.

6

Detailed Chemistry Near the Flammability Limits; Ethane - Air Mixtures

Kędzior R., Baczyńska T., Głowiński J., Hałat A.

Archivum Combustionis

|

2010

|

Vol. 30 nr 4

353-359

EN

To estimate the nature of combustion ethane-air mixtures the kinetic criterion of steady-state condition has been created and tested using algorithm PREMIX from CHEMKIN package. The process is fully branched inside the flammability region and increasing or decreasing equivalence ratio cause reduction of flame temperature as well as the rate of each elementary reaction. Nearby flammability limits criterion used points to steady-state conditions, i.e. chain carriers reach their steady-state, small concentrations. Hence, even small outer impulse can break chains branching and stop flame propagation.