A study was made on a trial hollow cone nozzle with regards to the relation between various factors of the nozzle (especially swirl chamber height and nozzle core inlet length) and its atomization characteristics.
In addition a spray distribution recording device was developed and the influence of the various factors of the hollow cone nozzle was studied.
The results were as follows;
1) Discharge coefficient (
Cl=0) affected the Reynold's number (
Re). In the range of this experiment (
Re: 1.0×10
4-5.6×10
4), the following empirical equation was derived.
C∞=
Cl=0·exp (
T/
Re), where
C∞ indicated the discharge coefficient under conditions of potential flow. The
C∞ increased with the increase in value of
h (swirl chamber height). When the nozzle parameter Ω was exactly at 0.4667, coefficient
T showed a distinct effect on h. Hence, it may be considered that when the value of Ω is greater than 0.4667, the fixed numaber
T is 1002.
2) The effect of the nozzle inlet length appeared distinctly, when the values of Ω is larger than 0.6770. The
C∞ showed lower values as the lenght increased.
3) It may be considered that by changing
h the nozzle parameter Ω may be changed. As the relation between (h/r) and Ω changed linearly, the following differential equation may be derived. ΔΩ/Δ(h/r)=5.29×10
-24) The droplet size distribution was clearly influenced by
h at a fixed pressure. It was noted that especially in relation to the above, the maximum diameter, mean diameter, their standard deviation increased with the increase in swirl chamber height. Sauter's mean diameter (
d0) was shown by the following equation which was obtained from the ratio of velocity at the orifice (
v/
ue).
d0=93.23+88.80×(
v/
ue)
5) It was comfirmed that the spray pattern changed from a hollow cone pattern to full cone pattern in accordance with the ascending pressure. And this tendency became extreme as h increased.
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