Simulation of a Multiphase flow in a Convergent-Divergent Nozzle

RR16988 · June 9, 2015, 07:06

Hello everyone,

I have been able to solve my initial problems with a De Laval nozzle, but now I have started trying to simulate a multiphase flow through a De Laval nozzle. The materials being used are Air ideal gas at 650 degree C and molten Zinc droplets (420 degree C). I need to create a separate inlet for the zinc droplets, and I have done it, but I am not sure if it is right. The zinc inlet should come at the inlet to the nozzle region. I calculated the values of mass flow rate, velocity, pressure and temperature of air at the nozzle inlet region with my initial model, which has just air ideal gas at 650 degree C as inlet material.

Attachment 40006 - The inital complete model with just air as inlet material

Then I deleted the starting part of the model, and sketched the model starting from the nozzle inlet. I have created the zinc inlet at this region, by creating a new plane, and transforming the Global X and Y, and sketching a rectangle at the air inlet, and extruding it. (I am not sure if this is the right method)

Attachment 40007 - The model with air inlet and zinc inlet

My question is, how can I set the zinc inlet to choose zinc as the material, and the air inlet to choose air as the material in Fluent? Moreover, how can I use zinc droplets as the inlet material, i.e. is there any way to choose droplets as an option somewhere? Also, shouldn't I turn the Multiphase flow option on? (The settings automatically are set to choose 'Wet steam' if I turn this option on. So, I am not sure about what this does either!) I chose the realizable k-epsilon model initially. I tried simulating by initializing both air-inlet and zinc-inlet as reference values, but my results weren't making any sense.

These are the parameters of the materials and the model:

At air inlet : Subsonic, Air ideal gas at 650 degree C, Pressure = 1000000 Pa, Mass flow rate = 0.017 kg/s
At zinc inlet : Zinc droplets of 0.1 mm diameter at 420 degree C (no idea about the pressure), Mass flow rate = 0.0028 kg/s
At outlet : Supersonic outlet, Pressure = 101325 Pa

I would appreciate any kind of help with my problem!

RR16988 · June 9, 2015, 07:10

NozzlesmoothmodelforCFDonline.jpg

This is my initial model with just air as inlet material

Attachment 40009

This is the model with the zinc inlet

June 9, 2015, 07:06	Simulation of a Multiphase flow in a Convergent-Divergent Nozzle	#1
RR16988 New Member Join Date: May 2015 Posts: 5 Rep Power: 11	Hello everyone, I have been able to solve my initial problems with a De Laval nozzle, but now I have started trying to simulate a multiphase flow through a De Laval nozzle. The materials being used are Air ideal gas at 650 degree C and molten Zinc droplets (420 degree C). I need to create a separate inlet for the zinc droplets, and I have done it, but I am not sure if it is right. The zinc inlet should come at the inlet to the nozzle region. I calculated the values of mass flow rate, velocity, pressure and temperature of air at the nozzle inlet region with my initial model, which has just air ideal gas at 650 degree C as inlet material. Attachment 40006 - The inital complete model with just air as inlet material Then I deleted the starting part of the model, and sketched the model starting from the nozzle inlet. I have created the zinc inlet at this region, by creating a new plane, and transforming the Global X and Y, and sketching a rectangle at the air inlet, and extruding it. (I am not sure if this is the right method) Attachment 40007 - The model with air inlet and zinc inlet My question is, how can I set the zinc inlet to choose zinc as the material, and the air inlet to choose air as the material in Fluent? Moreover, how can I use zinc droplets as the inlet material, i.e. is there any way to choose droplets as an option somewhere? Also, shouldn't I turn the Multiphase flow option on? (The settings automatically are set to choose 'Wet steam' if I turn this option on. So, I am not sure about what this does either!) I chose the realizable k-epsilon model initially. I tried simulating by initializing both air-inlet and zinc-inlet as reference values, but my results weren't making any sense. These are the parameters of the materials and the model: At air inlet : Subsonic, Air ideal gas at 650 degree C, Pressure = 1000000 Pa, Mass flow rate = 0.017 kg/s At zinc inlet : Zinc droplets of 0.1 mm diameter at 420 degree C (no idea about the pressure), Mass flow rate = 0.0028 kg/s At outlet : Supersonic outlet, Pressure = 101325 Pa I would appreciate any kind of help with my problem! Last edited by RR16988; June 9, 2015 at 07:06. Reason: spelling error

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June 9, 2015, 07:10		#2
RR16988 New Member Join Date: May 2015 Posts: 5 Rep Power: 11	NozzlesmoothmodelforCFDonline.jpg This is my initial model with just air as inlet material Attachment 40009 This is the model with the zinc inlet