gcmc of the flow of water

Hi, I’m doing a simulation of the flow of water.I want my water molecules to flow from one region to another.Here is my script.

variable T1 index 300
variable T2 index 150

dimension 3
boundary s s f
units metal

atom_style atomic

read_data Water_wall.data

group WALL type 1
group H2O type 2

pair_style hybrid lj/cut 2.5 sw
pair_coeff 1 1 none
pair_coeff 1 2 lj/cut 0.0067 3.166
pair_coeff * * sw mW.sw NULL Si

variable Z equal (zhi-zlo)/2+zlo

neighbor 0.5 bin
neigh_modify every 1 delay 0 check no

velocity H2O create ${T1} 940528 rot yes dist gaussian
velocity WALL set 0.0 0.0 0.0
fix FORCE WALL aveforce 0.0 0.0 0.0

fix wallX all wall/reflect xlo EDGE xhi EDGE
fix wallY all wall/reflect ylo EDGE yhi EDGE
fix wallZ all wall/reflect zlo EDGE zhi EDGE

group left dynamic H2O region L every 10
group right dynamic H2O region R every 10

fix MC left gcmc 10 10 10 2 940528 {T1} -0.7 0.5 region L fix NVTL left nvt temp {T1} {T1} 0.1 fix NVTR right nvt temp {T2} ${T2} 0.1

compute 2 all temp
compute_modify thermo_temp dynamic/dof yes

timestep 0.001

thermo_style custom time step pe etotal enthalpy density press temp
thermo 100

dump DUMP all custom 100 Water_wall2000.xyz id type xs ys zs

run 1000000
well,I have two problems that I cannot understand and solve.1. I set the command why can’t my water molecules flow?

  1. Under the command of GCMC, my temperature cannot be maintained at my preset temperature of 300K, and it rises to 3000K or even 7000K at some time in the middle. I don’t know why this happens?

please help me.thanks.

the bigger problem is: why do you need to use fix gcmc to induce a flow? that seems rather needlessly complicated to me.
there was a recent exchange on the mailing list on how to set up a flow simulation. search for “Simulation of flow via creation/elimination of atoms at boundaries” and look at the suggested alternative.