## Fluids

Topics relate to Fluent, CFX, Turbogrid and more

#### maximum temperature more than inlet temperature

• veera
Subscriber

Dear all

for my problem , inlet temperature is more than inlet temperature , i am using pressure based approach , transient conditions, density is ideal gas

even i monitored velocity also , it is very very low , so i cant sure about kinetic energy , and any other factor my temperature is more than inlet temperature

• KR
Hello,nHow are you calculating this inlet temperature? Please provide the necessary screenshots so we are able to understand this better? nAlso, what is the boundary condition at your inlet? What are the boundary conditions at the adjoining wall?nThank you.nKarthikn
• veera
Subscriber
GENERAL : P , TRANSIENTnMATERIAL: H2OnINLET: TWO INLET : VARYING PRESSURE BASED INLET CONDTIONS AND TEMPERATURE (EXPERIMENATL RESULTS)nOUTLET : CLOSEDnWALL : ADIABATIC AND HEAT FLUX = 0nnn
• Rob
Forum Moderator
Plot temperature, pressure and flow field so we can see what's going on. How well converged is the solution? n
• veera
Subscriber
That is well converged one sir , but I need to update one , I run simulation both the cases as pressure based approach and density based approach , nfor steady case approach , temperature is not existing the inlet temperature ..there its finenin transient approach , if i use constant inlet with pressure based approach .. temperature is not more than inlet temperature nbut when i use variable pressure boundary at inlet ..its more than inlet temperature for the both pressure and density based approachesnso please help me to resolve this issuesnn
• Rob
Forum Moderator
What variable pressure? How much warmer does the domain get? Remember as gas compresses it'll heat up. Assuming you're modelling with ideal gas. n
• veera
Subscriber
transient boundary condition setup at inlet , please have a look previous images , yes we are using ideal gas onlynn
• Rob
Forum Moderator
Flow enters the domain and doesn't leave. It's an ideal gas. Domain is adiabatic. If the pressure increases, what should the temperature do? n
• DrAmine
Ansys Employee
Hot hotn
• veera
Subscriber
but in steady case , this not the case wright , why only in transient pressure variable at inletn
• veera
Subscriber
thank you , rob sir np = rho * R * T neven temperature also i used to give variable temperaturen
• veera
Subscriber
so i gave p and T as input so , with that ideal equations are calculated , or what is the case sir n
• DrAmine
Ansys Employee
Hi,be patient when raising a question. While raising a question: provide all necessary information. Can you now summarize the whole problem in a single message?n
• veera
Subscriber
yes , DrAminenGENERAL : Pressure based approach , TRANSIENT conditionsnMATERIAL: H2O (ideal gas law)nINLET: TWO INLET : VARYING PRESSURE BASED INLET CONDTIONS AND TEMPERATURE (EXPERIMENATL RESULTS)nnOUTLET : CLOSED (wall adiabatic)nWALL : ADIABATIC AND HEAT FLUX = 0nnabove mentioned is basic setup for my problem , when i am running this setup , withinin few seconds i am getting average temperature inside the domain volume is more than inlet temperature what i am specified at variable temperature inletneven i approach the same setup with density based approach , I am getting same error (average temperature inside the domain more than inlet specified)n
• Rob
Forum Moderator
Please plot the volume average temperature on the same graph as the inlet temperature against time. Also post the convergence plot. Going back to my earlier question, why shouldn't the domain get warmer as you compress the gas?n
• veera
Subscriber
we not compressing the fluid , we plotted Mach number also . that is very very lessn convergence plotnn
• DrAmine
Ansys Employee
@veera, @Rob, asked for '..Please plot the volume average temperature on the same graph as the inlet temperature against time.'

we not compressing the fluid , we plotted Mach number also . that is very very less convergence plothttps://us.v-cdn.net/6032193/uploads/NILKTRM4JW3I/image.pnghttps://forum.ansys.com/discussion/comment/98545#Comment_98545

n