  We present the results of high-resolution AP3M+SPH simulations of merging
clusters of galaxies. We find that the compression and shocking of the core gas
during a merger can lead to large increases in bolometric X-ray luminosities
and emission-weighted temperatures of clusters. Cooling flows are completely
disrupted during equal-mass mergers, with the mass deposition rate dropping to
zero as the cores of the clusters collide. The large increase in the cooling
time of the core gas strongly suggests that cooling flows will not recover from
such a merger within a Hubble time. Mergers with subclumps having 1/8th of the
mass of the main cluster are also found to disrupt a cooling flow if the merger
is head-on. However, in this case the entropy injected into the core gas is
rapidly radiated away and the cooling flow restarts within a few Gyr of the
merger. Mergers in which the subcluster has an impact parameter of 500kpc do
not disrupt the cooling flow, although the mass deposition rate is reduced by
\~30%. Finally, we find that equal mass, off-centre mergers can effectively mix
gas in the cores of clusters, while head on mergers lead to very little mixing.
Gas stripped from the outer layers of subclumps results in parts of the outer
layers of the main cluster being well mixed, although they have little effect
on the gas in the core of the cluster. None of the mergers examined here
resulted in the ICM being well mixed globally.
