{"id":42392,"date":"2020-04-02T20:30:07","date_gmt":"2020-04-02T20:30:07","guid":{"rendered":"\/forum\/forums\/topic\/gas-mixture-nozzle-flow\/"},"modified":"2020-04-02T20:30:07","modified_gmt":"2020-04-02T20:30:07","slug":"gas-mixture-nozzle-flow","status":"closed","type":"topic","link":"https:\/\/innovationspace.ansys.com\/forum\/forums\/topic\/gas-mixture-nozzle-flow\/","title":{"rendered":"Gas Mixture Nozzle Flow"},"content":{"rendered":"

Hello<\/p>\n

I didnt find the solution for my problem in available CFX tutorials so I decided to try getting help here.<\/p>\n

I’m trying to simulate a steady state nozzle air flow with “holes” in the side wall as additional inlets for methane combustion exhaust fumes.<\/p>\n

A simplified solid is presented in a picture below.<\/p>\n

<\/p>\n

\"\"<\/p>\n

<\/p>\n

In fluid domain settings I would like to use “Air Ideal Gas” for the main Inlet (invisible in the picture, rectangular face from the side of coordinate arrows). The next aspect is is to define exhaust gases for side Inlets (in red circle): I used stoichiometric data from methane combustion, so I chose from the material library data four fluids:<\/p>\n

<\/p>\n

– CO2 Ideal Gas (Volume Fraction in Inlet Fluid Values – 0.095)
– Water Ideal Gas (Vol. Fraction 0.19)
– N2  Ideal Gas (Vol. Fraction 0.715)<\/p>\n

<\/p>\n

All of them as continuous Fluids; ref. pressure = 0; Non Buoyant Model; Stationary; None Mesh Deformation.<\/p>\n

<\/p>\n

And in Fluid Models I got the problems:
From ANSYS Help I got the information: In homogeneous multiphase flow, a common flow field is shared by all fluids, as well as other relevant fields such as temperature and turbulence. <\/p>\n

In my model the exhaust gases are joining the air flow and it’s not all mixed from the beginning. So I didnt use this option.<\/p>\n

The second option: Homogeneous Model of Heat Transfer I also didnt use, but if someone could explain this to me I would be grateful. I included Viscous Work Term and Total Energy (due to Kinetic energy impact I cannot use the Thermal Energy model).<\/p>\n

In Turbulence I didnt use Homogeneous Model neither and no combustion or thermal radation is considered.
I used the option “Fluid Dependent” Turbulence, so in Fluid Specific Models part I chose for all components  SST Turbulence Model with automatic wall function. <\/p>\n

And in the next part there is my biggest issue: In Fluid Par Models I have one “Mixture Model” Interphase Transfer with basic 1 mm Interface Len. Scale a basic Drag Coefficiend of 0.44 in Drag Force. None Mass Transfer is included. How can I properly specify Heat Transfer between each Fluid Pair? <\/p>\n

Boundary conditions
Main Air Inlet – Static Pressure 0.18 MPa, Zero Gradient Flow, Temp 900C, Volume Fraction Air 1, rest fluids 0.
Inlet 2 and 3 on the both sides of the nozzle: Static\/Total pressure will be calculated later, but I need to get an ejection of fumes into the nozzle; flow – normal to boundary and static temperature of 1300C. I will repeat the Volume Fractions for these Inlets:
– CO2  0.095
– Water Ideal Gas 0.19
– N2  Ideal Gas 0.715
– Air 0<\/p>\n

Outlet Av. Static Pressure 0.11 MPa (Ref. Pressure = 0). Wall of the nozzle is heated, and its’ fixed temperature is 1100C.
Wall Contact Model: Use Volume Fraction.<\/p>\n

 Archive file attached – “1”. <\/p>\n

<\/p>\n

 <\/p>\n","protected":false},"template":"","class_list":["post-42392","topic","type-topic","status-closed","hentry"],"aioseo_notices":[],"acf":[],"custom_fields":[{"0":{"_bbp_old_topic_id":["14572"],"_bbp_old_topic_author_name_id":["Anonymous"],"_bbp_old_is_topic_anonymous_id":["false"],"_bbp_old_closed_status_id":["publish"],"_bbp_author_ip":[null],"_bbp_old_sticky_status_id":["normal"],"_bbp_likes_count":["0"],"_btv_view_count":["1491"],"_bbp_topic_status":["unanswered"],"_bbp_status":["publish"],"_bbp_topic_id":["42392"],"_bbp_forum_id":["27792"],"_bbp_engagement":["22555","159776"],"_bbp_voice_count":["2"],"_bbp_reply_count":["12"],"_bbp_last_reply_id":["110729"],"_bbp_last_active_id":["110729"],"_bbp_last_active_time":["2020-04-09 05:39:25"]},"test":"mrmr"}],"_links":{"self":[{"href":"https:\/\/innovationspace.ansys.com\/forum\/wp-json\/wp\/v2\/topics\/42392","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/innovationspace.ansys.com\/forum\/wp-json\/wp\/v2\/topics"}],"about":[{"href":"https:\/\/innovationspace.ansys.com\/forum\/wp-json\/wp\/v2\/types\/topic"}],"version-history":[{"count":0,"href":"https:\/\/innovationspace.ansys.com\/forum\/wp-json\/wp\/v2\/topics\/42392\/revisions"}],"wp:attachment":[{"href":"https:\/\/innovationspace.ansys.com\/forum\/wp-json\/wp\/v2\/media?parent=42392"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}