DDG-51 class Hybrid propulsion RANGE?

[petsan]

After watching "the last ship" on TV I started wondering........(yea the Iowa subs for the Kirov class on the show)
The standard DDG-51 class can go 4,400 nautical miles at 20 knots
I was wondering with a 16% fuel saving with Hybrid.....how far will a hybrid equipped DDG-51 go on service turbine-generators at 15 knots ????

=============BLAH BLAH BLAH=================
Right now, DDG-51 destroyers are fielded with a ship service electrical system, and an independent main propulsion system of LM2500 gas turbines that are tied to a mechanical drive through the Main Reduction Gear assembly. Each shaft is tied to 2 LM2500 gas turbines (GTMs), which have just 2 speeds: off, and on. Another 3 ship service turbine-generators (GTGs) provide electrical power, with the 3rd designed as a redundant back-up. Using this mechanical arrangement, current DDG-51 Flight IIA ships have a reported total power output of 7.5 MW, and end up using too much effort from their LM2500 gas turbines for propulsion at low speeds.
During underway operations under 15 knots, in low-threat areas, 2 engines are typically on line: a gas turbine GTM with a trail shaft, and a smaller ship service turbine-generators GTG for basic power to the ship, navigation radars etc. Speed changes up to 15-18 knots are controlled by varying propeller pitch, and are independent of the LM2500 GTM. For more electricity, another GTG generator can be brought online to power the main SPY-1 radar if needed.
At low speeds, Hybrid Electric Drives would allow ships to take the gas turbines GTM offline, and rely on 1-2 smaller service turbine-generators GTGs for both propulsion and power, using less fuel and offering more power flexibility. Ships could also be designed with fixed-pitch propellers, which are quieter than variable-pitch blades. As a bonus, Hybrid Electric Drives (HED) propulsion is less noisy, which is useful when a ship is trying to deal with enemy submarines, hybrid electric drive also reduces fuel use and increases range by 16%, cutting each ship’s annual steaming cost by $2.5 million.

[desertswo]

After watching "the last ship" on TV I started wondering........(yea the Iowa subs for the Kirov class on the show)
The standard DDG-51 class can go 4,400 nautical miles at 20 knots
I was wondering with a 16% fuel saving with Hybrid.....how far will a hybrid equipped DDG-51 go on service turbine-generators at 15 knots ????

=============BLAH BLAH BLAH=================
Right now, DDG-51 destroyers are fielded with a ship service electrical system, and an independent main propulsion system of LM2500 gas turbines that are tied to a mechanical drive through the Main Reduction Gear assembly. Each shaft is tied to 2 LM2500 gas turbines (GTMs), which have just 2 speeds: off, and on. Another 3 ship service turbine-generators (GTGs) provide electrical power, with the 3rd designed as a redundant back-up. Using this mechanical arrangement, current DDG-51 Flight IIA ships have a reported total power output of 7.5 MW, and end up using too much effort from their LM2500 gas turbines for propulsion at low speeds.
During underway operations under 15 knots, in low-threat areas, 2 engines are typically on line: a gas turbine GTM with a trail shaft, and a smaller ship service turbine-generators GTG for basic power to the ship, navigation radars etc. Speed changes up to 15-18 knots are controlled by varying propeller pitch, and are independent of the LM2500 GTM. For more electricity, another GTG generator can be brought online to power the main SPY-1 radar if needed.
At low speeds, Hybrid Electric Drives would allow ships to take the gas turbines GTM offline, and rely on 1-2 smaller service turbine-generators GTGs for both propulsion and power, using less fuel and offering more power flexibility. Ships could also be designed with fixed-pitch propellers, which are quieter than variable-pitch blades. As a bonus, Hybrid Electric Drives (HED) propulsion is less noisy, which is useful when a ship is trying to deal with enemy submarines, hybrid electric drive also reduces fuel use and increases range by 16%, cutting each ship’s annual steaming cost by $2.5 million.

You are veering dangerously close to my personal and professional wheelhouse, and a lot of devils are in the details of your "blah, blah, blah." If one was going to go with one generator online, then why not have the LM2500s, unless one is absolutely wedded to the so called "cruising turbine" in the form of an Allison 501-K17, driving the alternator end, as your source of shipboard electricity for both ship's combat suite and hotel usage, and to drive your hybrid drive motors?

[petsan]

Navy Set to Install Hybrid Electric Drives in Destroyer Fleet Staring Next Year in 2016.......

http://news.usni.org/2015/09/23/navy...ring-next-year


Now that its official......any thoughts on range?

[JRT]

Navy Set to Install Hybrid Electric Drives in Destroyer Fleet Staring Next Year in 2016.......

http://news.usni.org/2015/09/23/navy...ring-next-year

Now that its official......any thoughts on range?

Firstly, Mike (desertswo) is an expert in this, and I am not. If he voices opinion on this, it is better informed than most.

There is some useful information available. Read the paper at the link below with consideration that in this application the biggest efficiency improvement comes with shutting down all four of the LM2500 gas turbines while operating at and below 13 knots. The paper partially illustrates historical utilization data where that might be applicable, 'if' there are no other changes in the way the ship is operated, and that is a rather big 'if'.

Reducing transit speed by 33% (say from 18 to 12 knots) reduces the power needed to turn the propellor shafts by more than 70%, but that also increases by 50% the time required to transit that distance. The hybrid electric drive does not reduce the power needed to turn the shafts to produce any particular speed, rather it provides means of transferring power from another source which may be producing that needed power more efficiently (source operating at lower brake specific fuel consumption, rate of fuel consumption divided by power produced) in some speeds and situations, and not in others (such as at speeds above 13 knots, and situations requiring quick availability of much higher speed and/or the increased power needed for higher latteral accelerations in turning).

Operational Ship Utilization Modeling of the DDG-51 Class
https://www.navalengineers.org/Proce...rson_Paper.pdf

Abstract — "Surface ship speed-time profiles (representations of the percentage of underway time spent at all speeds in ship’s speed range) are important points of reference when conducting conversion and trade studies, especially those that are concerned with increasing fuel efficiency. The speed-time profile for the DDG-51 class was originally estimated in 1994 using CG-47 data and has not been updated or validated since. This study provides a new profile, using actual current data taken from the deck and engineering logs of several ships. The result is considerably different from the version currently in use, and the impact these differences would have on trade study decisions are potentially very significant. Useful information not present in the current version, such as plant configuration and the ship’s operational posture, is also included."

[dundonrl]

Firstly, Mike (desertswo) is an expert in this, and I am not. If he voices opinion on this, it is better informed than most.

There is some useful information available. Read the paper at the link below with consideration that in this application the biggest efficiency improvement comes with shutting down all four of the LM2500 gas turbines while operating at and below 13 knots. The paper partially illustrates historical utilization data where that might be applicable, 'if' there are no other changes in the way the ship is operated, and that is a rather big 'if'.

Reducing transit speed by 33% (say from 18 to 12 knots) reduces the power needed to turn the propellor shafts by more than 70%, but that also increases by 50% the time required to transit that distance. The hybrid electric drive does not reduce the power needed to turn the shafts to produce any particular speed, rather it provides means of transferring power from another source which may be producing that needed power more efficiently (source operating at lower brake specific fuel consumption, rate of fuel consumption divided by power produced) in some speeds and situations, and not in others (such as at speeds above 13 knots, and situations requiring quick availability of much higher speed and/or the increased power needed for higher latteral accelerations in turning).

Operational Ship Utilization Modeling of the DDG-51 Class
https://www.navalengineers.org/Proce...rson_Paper.pdf

Abstract — "Surface ship speed-time profiles (representations of the percentage of underway time spent at all speeds in ship’s speed range) are important points of reference when conducting conversion and trade studies, especially those that are concerned with increasing fuel efficiency. The speed-time profile for the DDG-51 class was originally estimated in 1994 using CG-47 data and has not been updated or validated since. This study provides a new profile, using actual current data taken from the deck and engineering logs of several ships. The result is considerably different from the version currently in use, and the impact these differences would have on trade study decisions are potentially very significant. Useful information not present in the current version, such as plant configuration and the ship’s operational posture, is also included."

it would be interesting to see the same figures and spread sheet for the Navy's nuclear powered Cruisers of the 70's through early 90's. I do remember talking with Sailors stationed on the nuke cruisers, and they were always the "go to" ships, since you didn't need to worry about fuel for them.

[DonBelt]

It might have been nice had they saved a few Spruances and OHP's to use as test beds for this.

[GrayGhost1975]

The ex-Paul F. Foster is still around being used as a giant R/C ship. Also, how far "gone" are the 3 remaining non-VLS Ticos?

[DonBelt]

They are using alternate fuels on the Paul F., but she can't be used operationally. A few Spruances or OHP's converted to hybrid drive that could be used operationally would have provided a good test scenario. All water under the bridge now.

[ChrisV71]

The ex-Paul F. Foster is still around being used as a giant R/C ship. Also, how far "gone" are the 3 remaining non-VLS Ticos?

CG-51 has been sold for scrap and as far as I can tell is still in Philly just waiting her turn to be towed to the scrapyard.

CG-47 and CG-48 are too far gone. The Navy cut off their props, shafts, struts, rudders and sonar domes, in water, with a giant saw to reclaim the parts for inventory. (CG-51 got the same treatment as well)