布林克曼数（Br）是和流动的粘滞流体和管壁的热传导有关的无量纲，和聚合物生产的制程有关。布林克曼数有几种定义，以下是一种定义：

其中木

布林克曼数是粘滞扩散产生的热和分子传导传递的热之间的比例，也就是粘滞热和外部加热之间的比例，其比例越高，表示外部加热相对于粘滞热的比例越低，因此温度上升的越慢。

例如一个螺杆挤出机，让聚合物熔化需要的能量主要来自以下两个来源：

前者是由驱动挤压机的马达所提供，后者则是由加热器提供，布林克曼数就是这两种热源的比例。

The Brinkman number (Br) is a dimensionless number related to heat conduction from a wall to a flowing viscous fluid, commonly used in polymer processing. There are several definitions; one is

where

It is the ratio between heat produced by viscous dissipation and heat transported by molecular conduction. i.e., the ratio of viscous heat generation to external heating. The higher its value, the slower the conduction of heat produced by viscous dissipation and hence the larger the temperature rise.