Vertical Gas Turbines: Easy as Standing on Your Head
Standing on your head may not actually be easy but standing a 4000 hp gas turbine on its head and running it is easier than you might think. At least for Vericor and Mitsubishi Heavy Industries (MHI). MHI is an industrial packaging partner of Vericor’s and a specialist in gas turbine power installations.
The MHI vertical gas turbine package is unique in the world and it was created to fulfill one specific need: to put a lot of shaft power on as small a footprint as possible. It began with an idea at MHI, and they took it to Vericor who were already supplying them with conventional gas turbines.
The idea involved finding a new drive systems for flood control pumps, pumps that can move a lot of water in a short period of time. But often the space to install these pumps, which are permanent installations in strategic locations, is at an absolute premium. Footprint space in particular. The idea that emerged was to simply design a gas turbine package where the gas turbine would be standing vertical, not unlike a rocket, except with the exhaust facing upwards. In a gas turbine, the flow of the gas through the engine is not dependent on gravity or engine orientation in any way. Vericor’s marine and industrial engine product line are aeroderivative engines, derived from aircraft engines. Aircraft jet engines are designed to operate in the vertical orientation. Why not an industrial engine?
The idea was intriguing to Vericor and with MHI’s help, a development program was launched. The ASE 40 engine was selected as best matching the requirements of the expected pump units. Engineers were able to verify that the only things in the engine that were really subject to gravity were the two fluids, fuel and oil. By redesigning where the oil flowed and how it was collected, and where unburned fuel might collect and migrate, the necessary adjustments were made. “The redesigns were surprisingly uncomplicated” said TimBaur, Vericor Program Manager, “the accessory gearbox only required minor modifications to allow for better oil draining, allowing us to use the same basic design” he added.
Testing of course verified the accuracy of the analysis. The weight and contact signature of the rotor assembly in the engine at rest with the existing bearing packages as well within capability and design allowance. Once ignition is achieved and the engine is at idle, the load shifts slightly and all bearing parameters are within their design range.
MHI mates the engine, now called ASE40V, with a specially designed pump that can pump over 400,000 gal/min of water when operating at full capacity. This pump package can drain a common swimming pool in 4 seconds.
The success of the re-orientation was confirmed as the resulting packages realized a space savings of between 24 and 40% compared to conventional gas turbine packages. In an environment where the cost of space is at an ultimate premium, the level of savings makes standing on your head all that much smarter.