Um, you can't. A classic Rayleigh distribution has ONE parameter. Call it sigma.
The mean is:
The variance is:
If you wish to match TWO parameters, the mean and variance, you won't in general be able to get both right, at least unless you are very lucky in your choice of the mean and variance.
If you choose some non-standard Rayleigh that has two parameters, depending on what they are, you may have a chance.