solve a Heat ex changer question and its showing it has a Algebraic Loops error

It is a counterflow hot gas and air heat exchanger,we have three unknowns and three equations.

the input are:

T1IN: temperature of hot gas
T2IN: temperature of air
M1DOT: mass flow rate of gas
M2DOT; mass flow rate of air
C1: heat capacity of has
C2: heat capacity of air
U: heat transfers coefficient
A: heat transfer surface area

the output are

Q: 
T1OUT: gas temperature out
T2OUT: air temperature out

Three equations:

Q=C1*M1*(T1IN-T1OUT)
Q=C2*M2*(T2OUT-T2IN)
Q={U*A*(T1OUT-T2IN-T1IN+T2OUT)}/{LN(T1OUT-T2IN)/(T1IN-T2OUT)}

Answer 1

[Radha Krishna Maddukuri]

Hello,

I see that you have met with an algebraic loop in your Simulink Model.

To eliminate this message, you can do the following: Configuration Parameters(Ctrl+E) --> Diagnostics --> Algebraic Loop --> choose none from the drop-down.

However, as the error message points out, it is not a good practice to have Algebraic Loops in your model.

Therefore I suggest you to go through the following solution by MathWorks Support Team:

What are algebraic loops in Simulink and how do I solve them?

This solution gives a clear understanding of Algebraic loops, and it also sheds light on resolving them with better practices for modelling.

[Radha Krishna Maddukuri]

If you find the answer helpful, you can accept the answer, so that others who search for similar queries, may know that the answer was indeed helpful.

Answer 2

[MUHAMMED FASIL]

http://www.mathworks.com/videos/algebraic-loop-highlighting-99899.html