A three-dimensional geometric modelwas set up for the oxidative coupling of methane (OCM) fixed bed reactor loaded with Na

3

PO

4

-Mn/SiO

2

/cordierite monolithic catalyst

and an improved Stansch kinetic model was established to calculate the OCMreactions using the computational fluid dynamicsmethod and Fluent software. The simulation conditions were completely the same with the experimental conditions that the volume velocity of the reactant is 80 ml·min

-1

under standard state

the CH

4

/O

2

ratio is 3 and the temperature and pressure is 800 ℃ and 1 atm

respectively. The contour of the characteristic parameters in the catalyst bed was analyzed

such as the species mass fractions

temperature

the heat flux on side wall surface

pressure

fluid density and velocity. The results showed that the calculated valuesmatchedwell with the experimental values on the conversion of CH

4

and the selectivity of products (C

2

H

6

C

2

H

4

CO

CO

2

and H

2

) in the reactor outlet with an error range of ±4%. The mass fractions of CH

4

and O

2

decreased from 0.600 and 0.400 at the catalyst bed inlet to 0.44

5 and 0.120 at the outlet

where the mass fractions of C

2

H

6

C

2

H

4

CO and CO

2

were 0.0245

0.0460

0.0537 and 0.116

respectively. Due to the existence of laminar boundary layer

the mass fraction contours of each species bent upwards in the vicinity of the boundary layer. The volume of OCM reaction was changing with the proceeding of reaction

and the total moles of products were greater than reactants. The flow field in the catalyst bed maintained constant temperature and pressure. The fluid density decreased gradually from 2.28 kg·m

-3

at the inlet of the catalyst bed to 2.18 kg·m

-3

at the outlet of the catalyst bed

while the average velocity magnitude increased from 0.108 m·s

-1

to 0.120 m·s

-1

.