燃料气的流动速度 燃料气的流动速度与火焰的长短有密切关系，在外混式燃烧器中，燃料气流速过大，会引起脱火；在半预混燃烧器中，燃料气流速过小会引起回火。

There is a close relatihip between the flow velocity and flow velocity of flame fuel gas fuel gas in the length of the outer mixing burner, fuel gas flow rate is too large, will cause the removal of fire; in the semi premixed burner, fuel gas flow rate is too ***all will cause tempering.

燃料气的发热值:当其他条件相同时，燃料气的发热量越大，燃烧需要的空气量就越多，其混合时间也就越长。当炉子的燃料由热值低的燃料改为高热值燃料时，为了保证其完全燃烧，燃烧器在设计时需要注意改善燃料气与空气的混合条件。

The heating value of fuel gas when other conditi are the same, the greater the calorific value of fuel gas, the amount of air needed for burning more, the mixing time is longer. When the fuel of a furnace is changed from a fuel with low calorific value to a high calorific value fuel, in order to ensure its complete combustion, it is necessary to pay attention to improving the mixing condition of fuel gas and air in the design of the burner.

空气过剩系数:增大空气过剩系数，可以加速混合，使火焰变短，反之则混合缓慢，火焰拉长。这两种情况都有一些实际利用的例子。

Air surplus coefficient: increase the air surplus coefficient, can accelerate the mixing, make the flame shorter, and vice versa, slow mixing, flame elongated. There are some examples of practical use of these two cases.