A2-ShenliYuan

Interested Domain && Data Description

The topic I am interested in is how different composition of fuel/oxidizer change the properties in flames, specifically, flat flames generated by counter-flow burners. Basically this type of flames is generated in between two nozzles facing directly to each other. One nozzle (fuel nozzle) flows fuel (CH4, air (and may include H2)), the other nozzle (oxidizer nozzle) flows air only. This exploration helps us to improve the efficiency of combustion and possibly reduce the pollutant generated.

The dataset is from my previous research on combustion diagnostics, and I am only using the data that I have not produced visualization for. The datasets initially had very simple format: Temperature vs location for different cases. However during the exploration I computed the peak temperature and the half maximum thickness of flame. Also in order to plot multiple data series in one graph, I had to concatenate their location values in order to properly plot on Tableau.

Iteration 1

Question

How do different fuel/oxidizer ratios change the properties of the flame?

Visualization

Answer

This visualization demonstrate how different fuel composition change the properties of the flame. The different series of data in this visualization have different equivalence ratio (Phi). A higher equivalence ratio indicates higher fuel/oxidizer ratio of the gas. The fuel in this case is CH4. The visualization shows that in certain range, when we increase CH4 in the gas, the shape of flame is becoming thinner and thinner, and the peak temperature is decreasing.

This visualization shows us an overview of how the temperature distributions look like for different equivalence ratios. However it does not show the change of peak temperature very clearly.

Iteration 2

Question

How does the peak temperature change with equivalence ratio for the data above?

Visualization

Answer

In this visualization I extracted the peak flame temperature for the no H2 cases vs different equivalence ratios. The visualization shows that along with the increase of equivalence ratio, the peak temperature drops at first and reaches to the lowest value at some point, then rises again. This visualization sort of shows a certain pattern of change of peak temperature, but with insufficient data points given, it is really hard to tell exactly what the trend should be.

This visualization helps analyze the initial question, however there are other information in this dataset that could potentially result in interesting discovery. For example, certain flames in this datasets have H2 added to the fuel instead of having CH4 only.

Iteration 3

Question

How do different fuel/oxidizer ratios (with the same amount of H2 added) change the properties of the flame?

Visualization

Answer

The visualization shows that with the increase of equivalence ratio, and the same H2 added to the fuel, the flame become thinner and thinner, which is consistent with no H2 cases. The position of the flame also shifts to the fuel nozzle along higher equivalence ratio; this trend can also be observed in the previous plot; however the addition of H2 makes this trend more observable. Another thing that can be found is that there is no clear trend how peak temperature change with different equivalence ratios.

A common trend from iteration 1 and iteration 3 that I observed is that the flame becomes thinner as equivalence ratio increases. Now I want to see more closely about this trend.

Iteration 4

Question

How does flame thickness change along with the increase of equivalence ratio?

Visualization

Answer

In this visualization I calculated the flame half maximum thickness for the data in iteration 1 and iteration 3 vs equivalence ratios. This visualization shows that the flame thickness decreases as the equivalence ratio increases. The change is more steep when the equivalence ratio is small. Surprisingly, the addition of H2 seems not to have much effect on how thick the flame is.

So far I have analyzed how different equivalence ratio (No H2 added) change the properties of flame; how different equivalence ratio (same amount of H2 added) change the properties of the flame. However these two visualizations does not show how different amount of H2 (same equivalence ratio) change the properties of the flame.

Iteration 5

Question

How does different percentage of H2 (same equivalence ratio) change the properties of the flames?

Visualization

Answer

This visualization does show that different amount of H2 results in different flame properties (flame thickness, peak temperature, flame location, etc.) However it does not show a clear relationship of how the H2 percentage is related to these properties. From the visualization along, one might see that the peak temperature, flame thickness and flame location are more relevant to the boundary temperature at the fuel nozzle. But it is not clear if this temperature is relevant to different amount of H2 added.