Westinghouse LWNP
Contents
History
The Westinghouse Light Weight Nuclear Propulsion(LWNP) was an propulsion plant designed to be an drop-in replacement for either the LM2500 or FT4 Gas turbines in marine powerplants. It was based on existing technologies, notably those developed for nuclear rocket reactors. The LWNP consisted of an gas cooled nuclear reactor and an integrally packed gas turbine. In the paper describing this powerplant a few ship installations are proposed, none were ever build.
Used on
Affiliated systems
Part description
There are 2 setups drawin in the part image. The setup on the left has a full setup with an foot and gearbox such as would be found when installed on a ship. On the right is just the LWNP drawn. Both have a sideview (bottom) and top view (top). For placements in warships double units are shown in the source image, 1 on 1 replacing the double LM2500 units as found on for example Spruance class ships. In that installation the shielding overlaps (no need for shielding between the powerplants) in which case the shafts are 10' apart.
Alternate arrangements
While not specified in detail, the LWNP proposal also included provisions and rudimentary data for a 60,000 SHP variant. This proposed variant approximates an LM5000 engine module's footprint while providing the same benefits and disadvantages as the smaller LWNP unit. Although no data on dimensions are present in the proposal, a claimed specific power of approximately 15.6 lb/HP allows for an estimation of the larger LWNP footprint. Please note that the following data is speculative unless specified.
| Single LWNP unit data | ||||||
|---|---|---|---|---|---|---|
| Equivalent | Dimensions | Weight | SHP | Specific power | ||
| Length | Width | Height | ||||
| LM1600 | 25.5' | 10.1' | 11.3' | 539,706 lbs | 20,000 | 27.0 lbs/HP |
| LM2500 | 26.5' | 10.5' | 11.75' | 602,500 lbs | 25,000 | 24.1 lbs/HP |
| FT4A | 27.35' | 10.84' | 12.15' | 663,000 lbs | 30,000 | 22.1 lbs/HP |
| LM5000 | 30.7' | 12.15' | 13.6' | 936,000 lbs | 60,000 | 15.6 lbs/HP |
| LM5000 x 2 | 34.6' | 13.7' | 15.35' | 1,325,840 lbs | 120,000 | 11.0 lbs/HP |
Green represents known data; red represents estimations. LM1600 and LM5000 x 2 units are imaginary; no such plans exist.
Extrapolation method
While estimating the dimensions for the LM5000 equivalent unit, it is assumed that the density of the unit remains identical, representing a pure scaleup of the LM2500 equivalent unit. In practice, this may not have been the case; however, it is assumed to be a perfect scale of the smaller unit due to the limited information.
Known volume of 25kSHP unit given as:
l ⋅ w ⋅ h = v
Where density is constant in scaling up the system, volume is proportional to mass:
v ∝ m
A cube of the same volume has sides equal to:
3√v
Ratio of side lengths given as, where k is equal to a known dimension (l, w, or h) and vn is the new volume:
(ln) or (wn) or (hn) = 3√vn/(3√v/k) = k ⋅ 3√vn ⋅ v2/3/v
New dimensions given as ln, wn, and hn give new volume:
ln ⋅ wn ⋅ hn = vn
