Originally Posted by airfoilmod
,
The FOHE cools Oil. Fuel flows through 1,080 tubes with spaces between all of them between Face and Exit. This reduces cross section and increases Pressure and transit time. But the Oil gets cooled. There is a bypass for the Oil when further cooling is unnecessary, yet the Fuel must still transit the FOHE, regardless of Engine Demand. At this point, if max Fuel is commanded, and no Oil is being cooled, why, in your opinion, must the Fuel continue to flow through this necked down passageway, just to get to the HO side of the pumps for the FMU?
Not knowing, as we assume the designers did not know, that ice may be a problem, the question is: why not?
The fuel delivery system, including pumps, filters, and the path through the FOHE is obviously designed to be able to deliver maximum fuel flow needed for TOGA thrust, and then some.
Without our hindsight, nothing would have justified the additional weight and conplexity of a fuel bypass.
What is your opinion of the GE architecture: HP upstream the FOHE?
I'm not a fluid dynamics engineer, so I would have no opinion on that. I assumed from earlier pictures I saw that GE had a different layout of pumps and coolers than the Trents, but now I'm no longer so sure. I've read here with great interest about benefits and disadvantages of different designs, but I'm not in a position to judge any of that.
Bernd