The cross section of a heat exchanger consists of three circular pipes inside a larger pipe. The internal diameter of the three smaller pipes is D S = 1.5 cm, and their pipe wall thicknesses are each...

The cross section of a heat exchanger consists of three circular pipes inside a larger pipe. The internal diameter of the three smaller pipes is D_S
= 1.5 cm, and their pipe wall thicknesses are each 3 mm. The inside diameter of the larger pipe is D_L
= 11 cm. If the velocity of the fluid in the region between the smaller pipes and larger pipe is 13 m/s, what is the corresponding discharge in m³
/s?