# Q. How to define a energy source (sink) such that a specified temperature is maintained in the sub-domain?A. Set an Energy Source term in the required subdomain in the following form:Source = -C*Cp*(T-Tspec)where C is a large number (example 10E+8[kg m^-3 s^-1]), Cp is the specific heat capacity of the fluid, T is the local temperature and Tspec is the temperature that needs to be maintained in the sub-domain.The following CEL demonstrates how to implement this in CFX 5. (NOTE the value of the 'Source Coefficient' in the definition of the sub-domain source)CEL: EXPRESSIONS: Constant = 10E+8 [kg m^-3 s^-1] Tspec = 300 [K] heatsink = -Constant *Specific Heat Capacity at Constant Pressure *( T - Tspec) ENDENDSUBDOMAIN: sink Coord Frame = Coord 0 Location = B41 SOURCES: EQUATION SOURCE: energy Option = Source Source = heatsink Source Coefficient = -Constant*Specific Heat Capacity at Constant Pressure END ENDEND

 Q. How to define a energy source (sink) such that a specified temperature is maintained in the sub-domain?A. Set an Energy Source term in the required subdomain in the following form:Source = -C*Cp*(T-Tspec)where C is a large number (example 10E+8[kg m^-3 s^-1]), Cp is the specific heat capacity of the fluid, T is the local temperature and Tspec is the temperature that needs to be maintained in the sub-domain.The following CEL demonstrates how to implement this in CFX 5. (NOTE the value of the 'Source Coefficient' in the definition of the sub-domain source)CEL: EXPRESSIONS: Constant = 10E+8 [kg m^-3 s^-1] Tspec = 300 [K] heatsink = -Constant *Specific Heat Capacity at Constant Pressure *( T - Tspec) ENDENDSUBDOMAIN: sink Coord Frame = Coord 0 Location = B41 SOURCES: EQUATION SOURCE: energy Option = Source Source = heatsink Source Coefficient = -Constant*Specific Heat Capacity at Constant Pressure END ENDEND