Compressed air class A foam is a two-phase compressible non-Newtonian fluid with unbalanced self-organization structure. Numerical simulation of laminar flow of compressed air class A foam was studied. Foam with various expansion ratio could be used in different practical engineering. For the sake of guarantee on the reliability of the simulation

it is necessary to study on the compressibility and the rheological property of compressed air class A foam. As one kind of compressible fluid

the internal pressure of foam surges exponentially with the increase of the compression on the volume. In the process of compression

foam with different expansion ratio could keep stable without coalescence and breakage. In addition

foam with various expansion ratio has property of shear thinning while rheological behavior of foam satisfies with the model of Herschel-Bulkley. Taking the above factors into consideration

the numerical simulation software named Fluent was used to simulate the laminar flow of foam with various expansion ratio in the horizontal circular pipe of which the diameter is 15 mm and 25 mm. The pressure drop gradually increases with the flow process of the fluid when diameter of pipe is 15 mm. The downward trend of pressure in the pipe with diameter of 25 mm is relatively slow

while the pressure drop per meter is approximate to the fixed value. Verified by the experiment of foam transportation in pipe

this method possesses reliability and accuracy in a certain degree. The deviation of simulation could be controlled within 10%.