US 2010/0146953 A1Published application

Exhaust gas steam generation system

AssigneeDelphi Technologies, Inc.

InventorsMohinder S. Bhatti, Mark J. Zima, Prasad S. Kadle

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Abstract

A cylindrical stainless steel housing includes an exhaust inlet collar and exhaust outlet collar allowing exhaust gas to travel therethrough at a mean flow velocity in accordance with a velocity formula. A plurality of stainless steel tubes extend through the housing from a steam inlet manifold to a steam outlet manifold. A number and size of the tubes is determined by formulas and dependent on an Euler number, a Reynolds number, a number of transfer units, a Prandtl number, a porosity factor and a system efficiency. The tubes may comprise an S-shape or a U-shape. The tube walls have a thickness determined according to wall thickness formulas and the walls include a plurality of cavities on an interior surface of each tube wall. The cavities may comprise a conical or semi-spherical shape and have a diameter determined according to formulas.

Claims64

Dependent claims

An exhaust gas steam generation system for an automotive vehicle comprising:

a housing for conveying exhaust gas therethrough at a mean flow velocity (ve) in accordance with a velocity formula
v
e
=
4

m
.
e
πρ
e

D
wherein D is a predetermined diameter of said housing and {dot over (m)}e is a predetermined mass flow rate of said exhaust gas and ρe is a predetermined density of said exhaust gas;
a plurality of tubes extending through said housing for conveying said steam therebetween wherein the number (n) of said tubes is determined by a number formula
n
=
22.1


φ
Eu
e
5
/
8
wherein
Eu
e
=
Δ


p
e
ρ
e

v
e
2
/
2

g
c
and Δpe is a predetermined allowable pressure drop of said exhaust gas upon encountering said tubes and gc is a predetermined gravitational constant and φ is a predetermined porosity factor of said housing;
each of said tubes defined by a tube wall having an outside diameter (do) determined by an outside diameter formula do=0.2129DEue5/6;
each of said tube walls having a projected outside area (Ao) determined by an outside area formula
A
o
=
5.29

m
e

c
p
e

k
e

NTU
Pr
e
0.36

Re
d
0.63

d
o
wherein
NTU
=
ln

(
1
1
-
ɛ
)


and


Re
d
=
4

m
e

d
o
π


μ
e

D
2


and


ɛ
=
q
.
m
.
e

c
pe

(
T
e
-
T
s
)


and


c
pe

is a predetermined isobaric specific heat of said exhaust gas and {dot over (q)} is a predetermined rate of total heat transfer of said system and ke is a predetermined thermal conductivity of said exhaust gas and Pre is a predetermined Prandtl number of said exhaust gas and Te is a predetermined temperature of said exhaust gas and μe is a predetermined dynamic viscosity of said exhaust gas and Ts is a predetermined temperature of said steam;
and
each of said tubes having a length (l) dependent on said projected outside area (Ao) and in accordance with a length formula

=
A
o
π


nd
o
.

150 more elements

An exhaust gas steam generator system for an automotive vehicle comprising:

a housing defining a cylindrical shape and having a housing length and disposed around a housing axis extending between an exhaust inlet and an exhaust outlet on opposite sides of said housing for conveying exhaust gas therebetween at a mean flow velocity (ve) in accordance with a velocity formula
v
e
=
4

m
.
e
π


ρ
e

D
wherein D is a predetermined diameter of said housing and {dot over (m)}e is a predetermined mass flow rate of said exhaust gas and ρe is a predetermined density of said exhaust gas;
an exhaust inlet collar disposed around said housing axis (AH) and extending cylindrically from said housing for fixedly engaging an inlet exhaust pipe extending from an engine block of said automotive vehicle to convey said exhaust gas to said system;
an exhaust outlet collar disposed around said housing axis and extending cylindrically from said housing at said exhaust outlet for fixedly engaging an outlet exhaust pipe to discharge said exhaust gas from said automotive vehicle;
said housing including a steam inlet disposed around a first axis extending transversely to said housing axis for receiving steam;
said housing including a dry steam outlet disposed around a second axis extending transversely to said housing axis for discharging said steam;
a wet steam inlet manifold extending radially from and in sealed engagement with said housing at said wet steam inlet and disposed around a first axis extending transversely to said housing axis for fixedly engaging an inlet steam pipe extending from a heater of said automotive vehicle to convey said steam to said system;
a dry steam outlet manifold extending radially from and in sealed engagement with said housing at said dry steam outlet and disposed around a second axis extending transversely to said housing axis for fixedly engaging an outlet steam pipe extending to a passenger compartment of said automotive vehicle;
a plurality of tubes extending through said housing from said wet steam inlet manifold to said dry steam outlet manifold for conveying said steam therebetween wherein the number (n) of said tubes is determined by a number formula
n
=
22.1


φ
Eu
e
5
/
8
wherein
Eu
e
=
Δ


p
e
ρ
e

v
e
2
/
2

g
c
and Δpe is a predetermined allowable pressure drop of said exhaust gas upon encountering said tubes and gc is a predetermined gravitational constant and φ is a predetermined porosity factor of said housing;
said number (n) of said tubes being twelve tubes including four central tubes and eight outside tubes spaced about said four central tubes;
said plurality of tubes extending in spaced and parallel relationship to one another along a tube axis between tube ends in sealed engagement with said manifolds;
each of said tubes defined by a tube wall having an outside diameter (do) determined by the outside diameter formula do=0.2129DEue5/6;
each of said tube walls having a projected outside area (Ao) determined by an outside area formula
A
o
=
5.29

m
e

c
p
e

k
e

NTU
Pr
e
0.36

Re
d
0.63

d
o
wherein
NTU
=
ln

(
1
1
-
ɛ
)


and


Re
d
=
4

m
e

d
o
π


μ
e

D
2


and


ɛ
=
q
.
m
.
e

c
pe

(
T
e
-
T
s
)


and


c
pe
is a predetermined isobaric specific heat of said exhaust gas and {dot over (q)} is a predetermined rate of total heat transfer of said system and ke is a predetermined thermal conductivity of said exhaust gas and Pre is a predetermined Prandtl number of said exhaust gas and Te is a predetermined temperature of said exhaust gas and μe is a predetermined dynamic viscosity of said exhaust gas and Ts is a predetermined temperature of said steam;
each of said tubes having a length being less than said housing length (lh) and being dependent on said projected outside area (Ao) and in accordance with a length formula
l
=
A
o
π


nd
o
,
each of said tube walls having an interior surface defining a plurality of cavities disposed between said tube ends for promoting nucleate boiling in the flow of said steam therethrough;
each of said cavities having a circular periphery with a cavity diameter determined by a cavity diameter formula
d
c
=
7.5
×
10
-
5

g


σ
g
c

(
ρ
f
-
ρ
g
)

(
ρ
f

c
f

T
s
ρ
g

h
fg
)
5
/
4
wherein g is a predetermined acceleration due to gravity and ρf is a predetermined density of said steam in a liquid phase and σ is a predetermined surface tension of said steam in said liquid phase and cf is a predetermined specific heat of said steam in said liquid phase and ρg is a predetermined density of said steam in a gas phase and hfg is a predetermined latent heat of condensation of dry steam;
said cavity diameter (dc) being in a range between 0.250 mm and 1.250 mm;
each of said tube walls defined by a wall thickness being greater than a minimum wall thickness (δmin) determined by a minimum wall thickness formula
δ
min
≥
P
s

d
c
4

σ
yw
wherein σyw is a predetermined yield strength of the material of said tubes and Ps is a predetermined vapor pressure of said steam;
said minimum wall thickness (δmin) being in a range between 0.025 and 0.125 mm;
each of said tube walls further defined by said wall thickness (δ) being less than a maximum wall thickness (δmax) determined by a maximum wall thickness formula
δ
max
=
δ
min
+
d
c
2
;
said maximum wall thickness (δmax) being in a range between 0.150 and 0.750 mm;
and
said system comprising stainless steel.

234 more elements

A method for fabricating an exhaust gas steam generation system for an automotive vehicle comprising a housing to convey exhaust gas therethrough and a plurality of tubes extending through the housing to convey steam therethrough comprising:

determining the velocity of the exhaust gas through the housing according to a velocity formula
v
e
=
4

m
.
e
π


ρ
e

D
wherein D is a predetermined diameter of the housing (20) and {dot over (m)}e is a predetermined mass flow rate of the exhaust gas and ρe is a predetermined density of the exhaust gas;
determining the Euler number (Eue) for the housing according to an Euler number formula
Eu
e
=
Δ


p
e
ρ
e

v
e
2
/
2

g
c
wherein Δpe is a predetermined allowable pressure drop of the exhaust gas upon encountering the tubes and gc is a predetermined gravitational constant;
determining the outside diameter (do) of each of the tubes according to an outside diameter formula do=0.2129DEue5/6;
determining the number of tubes (n) extending through the housing from the wet steam inlet manifold to the dry steam outlet manifold for conveying the steam therebetween according to a number formula
n
=
22.1

φ
Eu
e
5
/
8
wherein φ is a predetermined porosity factor of the housing;
determining the dimensionless Reynolds number (Red) based on the outside diameter (do) of the tubes according to a Reynolds number formula
Re
d
=
4

m
e

d
o
π


μ
e

D
2
wherein μe is a predetermined dynamic viscosity of the exhaust gas;
determining the effectiveness (ε) of the system according to an effectiveness formula
ɛ
=
q
.
m
.
e

c
pe

(
T
e
-
T
s
)
wherein {dot over (q)} is a predetermined rate of total heat transfer of the system and cpe is a predetermined isobaric specific heat of the exhaust gas and Te is a predetermined temperature of the exhaust gas and Ts is a predetermined temperature of the steam;
determining the thermal size of the system represented by the number of transfer units (NTU) according to a number of transfer units formula
NTU
=
ln

(
1
1
-
ɛ
)
;
determining a desired outside area (Ao) of each tube according to an outside area formula
A
o
=
5.29

m
e

c
p
e

k
e

NTU
Pr
e
0.36

Re
d
0.63

d
o
wherein cpe is a predetermined isobaric specific heat of the exhaust gas and ke is a predetermined thermal conductivity of the exhaust gas and Pre is a predetermined Prandtl number of the exhaust gas;
and
determining the tube length () of each tube being less than the housing length (lh) and dependent on the desired outside area (Ao) and according to a tube length formula
l
=
A
o
π


nd
o
.

140 more elements

A method for fabricating an exhaust gas steam generator system for an automotive vehicle comprising a housing having a housing length (lh) to convey exhaust gas therethrough and a plurality of tubes extending through the housing to convey steam therethrough comprising:

determining the velocity of the exhaust gas through the housing according to a velocity formula
v
e
=
4


m
.
e
π


ρ
e

D
wherein D is a predetermined diameter of the housing and {dot over (m)}e is a predetermined mass flow rate of the exhaust gas and ρe is a predetermined density of the exhaust gas;
determining the Euler number (Eue) for the housing according to an Euler number formula
Eu
e
=
Δ


p
e
ρ
e

v
e
2
/
2


g
c
wherein Δpe is a predetermined allowable pressure drop of the exhaust gas upon encountering the tubes and gc is a predetermined gravitational constant;
determining the outside diameter (do) of each of the tubes according to an outside diameter formula do=0.2129DEue5/6;
determining the number of tubes (n) extending through the housing from the wet steam inlet manifold to the dry steam outlet manifold for conveying the steam therebetween according to a number formula
n
=
22.1


φ
Eu
e
5
/
8
wherein φ is a predetermined porosity factor of the housing;
determining the dimensionless Reynolds number (Red) based on the outside diameter (do) of the tubes according to a Reynolds number formula
Re
d
=
4


m
e

d
o
π


μ
e

D
2
wherein μe is a predetermined dynamic viscosity of the exhaust gas;
determining the effectiveness (ε) of the system according to an effectiveness formula
ɛ
=
q
.
m
.
e

c
pe

(
T
e
-
T
s
)
wherein {dot over (q)} is a predetermined rate of total heat transfer of the system and cpe is a predetermined isobaric specific heat of the exhaust gas and Te is a predetermined temperature of the exhaust gas and Ts is a predetermined temperature of the steam;
determining the thermal size of the system represented by the number of transfer units (NTU) according to a number of transfer units formula
NTU
=
ln

(
1
1
-
ɛ
)
;
determining a desired outside area (Ao) of each tube according to an outside area formula
A
o
=
5.29


m
e

c
p
e

k
e

NTU
Pr
e
0.36

Re
d
0.63

d
o
wherein cpe is a predetermined isobaric specific heat of the exhaust gas and ke is a predetermined thermal conductivity of the exhaust gas and Pre is a predetermined Prandtl number of the exhaust gas;
determining the tube length () of each tube dependent on the desired outside area (Ao) and according to a tube length formula
l
=
A
o
π


nd
o
;
determining a cavity diameter (dc) for a plurality of cavities on an interior surface of each tube according to a cavity diameter formula
d
c
=
7.5
×
10
-
5

g


σ
g
c

(
ρ
f
-
ρ
g
)

(
ρ
f

c
f

T
s
ρ
g

h
fg
)
5
/
4
wherein g is a predetermined acceleration due to gravity and σ is a predetermined surface tension of the steam in a liquid phase and ρf is a predetermined density of the steam in a liquid phase and cf is a predetermined specific heat of the steam in the liquid phase and ρg is a predetermined density of the steam in a gas phase and hfg is a predetermined latent heat of condensation of dry steam;
determining a minimum tube wall thickness (δmin) of each tube according to a minimum wall thickness formula
δ
min
≥
P
s

d
c
4


σ
yw
wherein σyw is a predetermined yield strength of the tubes and Ps is a predetermined vapor pressure of the steam;
determining a maximum wall thickness (δmax) of each tube according to a maximum wall thickness formula
δ
max
=
δ
min
+
d
c
2
;
extruding a metal sheet comprising stainless steel and having a thickness greater than the minimum wall thickness (δmin) and less than the maximum wall thickness (δmax);
rolling the cavities having the cavity diameter determined by the cavity diameter formula and having an inside area into the metal sheet;
cutting the metal sheet into a number of elongated strips being equal to the number of tubes and each elongated strip having a length equal to the tube length and a width dependent on the outside diameter of the tubes and determined by a width formula w=πdo;
welding the elongated strips into the plurality of tubes having the outside diameter and tube length;
fabricating the housing defining a cylindrical shape around a housing axis and having the predetermined diameter and having the housing length being greater than the tube length;
said fabricating the housing including fabricating an exhaust inlet collar extending radially around the housing axis and extending cylindrically from the housing to receive the exhaust gas;
said fabricating the housing including fabricating an exhaust outlet collar extending radially around the housing axis and extending cylindrically from the housing in opposite direction from the exhaust inlet collar to discharge the exhaust gas;
fabricating a wet steam inlet manifold extending radially around a first axis transverse to the housing axis;
fabricating a dry steam outlet manifold extending radially around a second axis transverse to the housing axis;
sealing the wet steam inlet manifold and the dry steam outlet manifold to the housing;
extending the tubes through the housing from the wet steam inlet manifold to the dry steam outlet manifold;
fixedly engaging a first tube end of each of the tubes to the wet steam inlet manifold;
fixedly engaging a second tube end of each of the tubes to the dry steam outlet manifold;
fixedly engaging the wet steam inlet manifold to an inlet steam pipe extending from a heater of the automotive vehicle to convey the steam to the system;
fixedly engaging the dry steam outlet manifold to an outlet steam pipe extending to a passenger compartment of the automotive vehicle to heat the passenger compartment;
fixedly engaging the exhaust inlet collar to an inlet exhaust pipe extending from an engine block of the automotive vehicle to convey the exhaust gas to the system;
and
fixedly engaging the exhaust outlet to an outlet exhaust pipe to discharge the exhaust gas from the automotive vehicle.

232 more elements

Dependencies are inferred from the claim text.

Facts

Application: 12/333,593Filed 12 Dec 2008
Published: 17 Jun 2010
Term ends: Not estimatedThe source records don’t support an estimate.

Classification14 codes

F01N 5/02
Exhaust or silencing apparatus combined or associated with devices profiting by exhaust energy: the devices using heat
F28D 7/005
Heat-exchange apparatus having stationary tubular conduit assemblies for both heat-exchange media, the media being in contact with different…
F28D 7/06
Heat-exchange apparatus having stationary tubular conduit assemblies for both heat-exchange media, the media being in contact with different…
F28D 7/08
Heat-exchange apparatus having stationary tubular conduit assemblies for both heat-exchange media, the media being in contact with different…