CA1036447A - Recirculation barrier for a heat transfer system - Google Patents
Recirculation barrier for a heat transfer systemInfo
- Publication number
- CA1036447A CA1036447A CA213,118A CA213118A CA1036447A CA 1036447 A CA1036447 A CA 1036447A CA 213118 A CA213118 A CA 213118A CA 1036447 A CA1036447 A CA 1036447A
- Authority
- CA
- Canada
- Prior art keywords
- fan
- air
- radiator
- shroud
- plane
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
- 230000004888 barrier function Effects 0.000 title abstract description 20
- 238000001816 cooling Methods 0.000 abstract description 12
- 238000002485 combustion reaction Methods 0.000 abstract description 6
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 6
- 238000012986 modification Methods 0.000 description 3
- 230000004048 modification Effects 0.000 description 3
- 230000007704 transition Effects 0.000 description 3
- 230000001419 dependent effect Effects 0.000 description 2
- 239000007788 liquid Substances 0.000 description 2
- 230000000712 assembly Effects 0.000 description 1
- 238000000429 assembly Methods 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 230000001627 detrimental effect Effects 0.000 description 1
- 238000007599 discharging Methods 0.000 description 1
- 239000012530 fluid Substances 0.000 description 1
- 239000002184 metal Substances 0.000 description 1
Classifications
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
- F01P—COOLING OF MACHINES OR ENGINES IN GENERAL; COOLING OF INTERNAL-COMBUSTION ENGINES
- F01P5/00—Pumping cooling-air or liquid coolants
- F01P5/02—Pumping cooling-air; Arrangements of cooling-air pumps, e.g. fans or blowers
- F01P5/06—Guiding or ducting air to, or from, ducted fans
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
- F04D—NON-POSITIVE-DISPLACEMENT PUMPS
- F04D19/00—Axial-flow pumps
- F04D19/002—Axial flow fans
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
- F04D—NON-POSITIVE-DISPLACEMENT PUMPS
- F04D29/00—Details, component parts, or accessories
- F04D29/40—Casings; Connections of working fluid
- F04D29/52—Casings; Connections of working fluid for axial pumps
- F04D29/54—Fluid-guiding means, e.g. diffusers
- F04D29/541—Specially adapted for elastic fluid pumps
- F04D29/545—Ducts
- F04D29/547—Ducts having a special shape in order to influence fluid flow
Landscapes
- Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- General Engineering & Computer Science (AREA)
- Physics & Mathematics (AREA)
- Fluid Mechanics (AREA)
- Chemical & Material Sciences (AREA)
- Combustion & Propulsion (AREA)
- Structures Of Non-Positive Displacement Pumps (AREA)
Abstract
RECIRCULATION BARRIER FOR
A HEAT TRANSFER SYSTEM
ABSTRACT OF THE DISCLOSURE
An internal combustion engine, having a heat exchange cooling system, a fan for moving air therethrough and a fan shroud and shroud exit section for controlling the air path. The shroud exit encloses the fan and in-cludes throat (CF) radial expander (R) and radial flat (RF) sections whereby air is drawn through the heat exchanger axially and expelled radially along said exit sections. The fan has a projected axial width (AW) such that a genera] relationship exists with the shroud exit sections: CF = AW/3, RF = AW/3, and R = 2AW/3. A barrier located behind the fan and away from the heat exchanger eliminates air recirculation in the fan hub region.
A HEAT TRANSFER SYSTEM
ABSTRACT OF THE DISCLOSURE
An internal combustion engine, having a heat exchange cooling system, a fan for moving air therethrough and a fan shroud and shroud exit section for controlling the air path. The shroud exit encloses the fan and in-cludes throat (CF) radial expander (R) and radial flat (RF) sections whereby air is drawn through the heat exchanger axially and expelled radially along said exit sections. The fan has a projected axial width (AW) such that a genera] relationship exists with the shroud exit sections: CF = AW/3, RF = AW/3, and R = 2AW/3. A barrier located behind the fan and away from the heat exchanger eliminates air recirculation in the fan hub region.
Description
36~7 RECIRCULATION ~ARRIER FOR
A HEAT TRANSFER SYSTEM
SPECIFICATION
This invention relates to a cooling assembly and more particularly to a fan shroud, a contoured fan shroud exit section and a fan located therein which has an air obstruction barrier therebehind. Reference should be made to my copending Canadian applications Serial Numbers 184,880 and 184,881, both filed November 2, 1973.
Most vehicles in general used today are driven by internal combustion engines. These engines being heat produc-ing are for the most part water cooled, that is, the engine is jacketed for circulation of water which takes up the heat and subsequently transfers it to the atmosphere. The radiator is used for cooling the liquid circulating through the engine by dissipating the heat to an air stream. The air flowing through the radiator absorbs the heat and carries it out into the atmosphere. Different types of fan systems are used to achieve the necessary air velocity through the radiator.
That is, some fan assemblies draw air from the atmosphere through the radiator and back over the engine thereafter exiting to the atmosphere. This type of fan is known as an axial flow suction fan, drawing air axially through the radi-ator and discharging it into the engine compartment. Other fans work in the reversed manner, that is, they draw air from the engine compartment wherefrom it is blown forwardly through the radiator to achieve the necessary radiator cooling.
Under optimum conditions it is believed prior art fans normally employ only about 1/3 of the length of the fan blade for the movement of air through the heat exchanger. The outer 1/3 of the blade length or tip regions, pulls in air from behind the shroud and recirculates it. The inner 1/3 or, hub region, pulls in air from the rear which it thereafter dis-``` ~036~7 charges rearwardly. As a result of these conditions onlyabout the middle 1/3 of the fan blade is effective in moving a cooling stream of air past the heat exchanger.
It has been shown, see copending Canadian application Serial Number 184,880, that a contoured shroud exit reduces horsepower requirements and generated noise and hampers the recirculation of air in the tip regions of the fan blade because of the radial air discharge pattern generated thereby.
Employment of the contoured shroud exit thus, increases the amount of the fan blade which is effective for moving air past the heat exchanger means.
It is therefore an object of this invention to provide an air barrier means to prevent the drawing in and recircul-ation of air from behind the fan blade. Still another object of this invention is to provide an air barrier means which does not interfere with the flow of air in the tip regions of the fan blade. Yet another object of this invention is to provide an air barrier means which functions as a safety guard. Another object of this invention is to provide a cooling assembly wherein a majority of the length of fan blade is functioning to move air each past the heat exchanger.
Broadly, the invention attains that object with a heat exchange apparatus which comprises a generally upright radiator having air intake and air discharge faces, and a rotatable multi-bLaded, axial flow, suction-type fan having a hub positioned on one side of the radiator adjacent the air discharge face for drawing air through the radiator axially in a direction from the air intake face to the air discharge face with the air flow through the radiator having a major component parallel ... .. .
with respect to the rotational axis of the fan with the blades having an effective axial width (AW) measured axially along the rotational axis of the fan between a first plane and a second plane. The planes are axially spaced and parallel with respect to each other and disposed substantially normal to the rotational ~3~47 axis of the fan. The first and second planes extend radially, respectively, through points on the leadiny edges of the blades at the radial tip portions thereof and through points on the trailing edges of the blades at the radial tip portion thereof.
A shroud means having one axial end operatlvely connected to the radiator encircles the fan, with the shroud means being shaped and positioned with respect to the radiator and the blades of the fan whereby the major component of air stream discharged by the fan is in a direction perpendicular to the direction of the major component of the air stream entering the air intake face and flowing through the radiator, and the axial end of the shroud means remote from the axial end operatively connected to the radiator is defined by an annular, radiaily outwardly extending flat portion lying substantially in a plane disposed perpendicular to the rotational axis of the fan and being substantially coin-cident with one of the first and second planes. A means is posi-tioned axially on the side of the fan opposite the radiator for obstructing flow of air axially through the fan at the hub region thereof in an axial direction opposite the direction of the major component of air flow through the radiator, with the means lying substantially in a plane spaced and substantially parallel with respect to the plane in which the flat portion of the shroud means lies.
j In accordance with the preferred embodiment of this inven-tion a vehicle is provided having a liquid cooled internal com-bustion engine and a radiator cooling system for dissipating the heat produced. The radiator cooling system includes a standard radiator, an axial flow fan facing the radiator and having a plurality of angular blades whereby air is drawn rearwardly through the radiator. A shroud rearwardly extends from the back face of the radiator to channel air through the radiator and hamper the fan from drawing air which has not passed through or at least come in contact with the perforated heat exchanging .
1(~369~47 surfaces of the radiator. For the most part the shroud encloses the entire perforated heat exchanging rear area of the radiator.
A fan shroud exit means is also provided having secured to the backwardly extending portion of the fan shroud and extending rearwardly thereof as well as outwardly. The particular contour of this exit section in combination with an axial flow fan located therein, allows the air stream to be converged and directed generally radially away from the engine compartment. Situated behind the fan is an air barrier means which in combination with the shroud exit section forces the fan to draw air through the radiator. As is apparent this invention is also applicable to a stationary engine where it is desired to achieve a high degree of performance from the fan blades.
Other objects and advantages of the invention will become apparent upon reading the following detailed description and upon reference to the drawings, in which;
FIGURE 1 is a side elevation of an internal combustion engine showing the combination of my invention with a contoured shroud exit section attached to a vehicle;
FIGURE 2 is a ~ragmentary vertical section showing the relationship o the fan, the contoured exit section, and the air flow pattern without an air barrier; and FIG~RE 3 is a fragmentary vertical section showing the air flow pattern with an air barrier.
, While the invention will be described in connection with a preferred embodiment, it will be understood that it is not intended to limit the invention to that embodiment- On the contrary, it is intended to cover all alternatives, modifications and equivalents as may be included within the spirit and scope ,of this invention as defined by the appended claims.
Turning first to Figure 1 there is shown a conventional water cooled heat producing internal combustion engine means 10 forwardly carried on longitudinally extending parallel support means 12 of vehicle means 14.
.
, -5-~. .
~(33~ 7 As shown herein vehicle means 14 is a tractor, however, as will hereafter become more apparent this invention can be applied to any type of vehicle employing a heat generating internal combustion engine or any other portable or stationary device requiring an air moving fan. For-wardly mounted is a water cooling radiator means 16 employed to dissipate the engine generated heat. Water flows between the water jacket on the engine (not shown) ; and the radiator through a series of fluid communicating means 18 and 20. In this particular embodiment sheet metal means 22 encircles engine means 10 thereby forming the engine compartment area means 24.
Carried at the forward end of engine means 10 is a fan shaft means 26 whereby power is delivered to drive fan means 28 (Figure 2). As is apparent, the particular mode whereby power is transmitted thereto is not critical and belts and pulleys could also be employed. As employed here, fan means 28 is a rotatable suction fan positioned opposite the radiator means 16, and normall~ creating a 10w of air or drawing in a stream of cooling air rearwardly through the radiator with a subsequent axial discharge thereof. This axial flow of air is directed to the fan means by a shroud means 30. The particular shape of the forward section 32 is dependent upon the shape and design of the perforated heat exchanging design of the radiator. The nature of the connection bstween the leading edge of 32 and the rear face 34 of the radiator will be dependent upon the particular characteristics of these components, that is, some connections being provided with air gaps while others ~a36~47 are substantially sealed over the entire circumference of the enclosure. In the preferred form of this inven-tion the entire perforated area is substantially sealed against the passage of air from any other direction except through the radiator. From the forward edges the shroud means 30 (be it a taper transition as shown or a box type) converges rearwardly to a circular rear section 36. An air barrier means 31 is positioned rearwardly of the shroud exit section 38 as will be more fully hereafter discussed.
Referring now to Figure 2 wherein is more clearly shown a shroud exit means 38 extending rearwardly and outwardly from shroud edge 36. The connection between the shroud and the shroud exit can be achieved by any suitable means, however, it is desirable that such con-nection be relatively free of gaps or spaces which would allow the passage of air. Exit shroud means 38 includes a tubular means 40, an arcuated means portion 42 and a flat flange portion means 44. For the most part tubular means portion 40 forms the leading edge of the shroud exit means while arcuated means portion 42 still extend-ing generally rearwardly simultaneously extends outwardly around an arc the reference point of which is defined as point 46. That is, arcuated section 42 has a general bell-shaped appearance being a section of a transition surface or some approximation thereof. In the preferred embodiment arcuated section 42 is a section of a constant radius arch. Flat flange portion 44 forms the trailing edge of exit shroud means 38 and has a major plane per-pendicular to that of tubular section 40. For purposes - ~3~4~
of simplicity, tubular means 40 will be hereafter referred to as the cylindrical throat means, arcuated portion 42 will be referred to as the radial expanding means and flat flange portion 44 will be referred to as radial flat means. Overall the entire fan shroud exit means 38 has a horn-like configuration.
The fan means 28 is rotatingly carried adjacent said radiator means and operable to establish a flow of cooling air therethrough.
Fan means 28 includes a plurality of fan blade means 48 (only one shown) as is well known in the art. As shown in Figure 2 fan means 28 is surrounded by said contoured fan shroud exit section 38. The enclosure of the fan means 28 within shroud means 30 is such that a front plane struck out by the leading edge 50 is coextensive and passes through the leading section of throat means 40 and a rear plane struck out by trailing edge 52 is about coextensive and parallel with said radial flat portion 44. It should be noted, however, that there is a plus or minus error factor involved in both of these values of about 12 percent of AW. That is, the respective planes formed by the blade means can be within about 12 percent of optimum and still function satisfactorily within the scope of this invention. Thus, within this range the deflected air stream will still be substantially radial. And generally about the outer two/thirds of the blade means is efficiently moving air through the radiator means.
While a beneficial effect is achieved by spacing the fan blades 48 with respect to the contoured shroud means 38 within the afor`ementioned range, it has been determined that best results are obtained when the front or first vertical plane struck out by the leading edges 50 of the fan blades 48 pass through the juncture or merger between the entrance shroud means 32 and the cylindrical exit shroud section 40. Even more determinative on the result is the relationship between the so-called rear plane struck out by the trailing edges 52 of the fan blades 48 and the radial flat flange shroud portion 44. Best overall performance is achieved when the rear or second vertical plane and the radial flat flange shroud portion or section 44 lie in the same plane.
_ Q _ ~ 47 The following relationship exists between these parameters: RF = AW/3, CF = AW/3, and R = 2AW/3 where RF is the length of the radial flat portion 44, CF is the length of the cylindrical throat section 40 and R is a radius of the radial expanding section 42 or distance from the reference point to the transition surface and AW is the projected axial width of fan 28.
The amount or relation of the fan means 28 to the exit section means 38 is most conveniently expressed in terms of the amount of the fan which is exposed past the end of the shroud or projects rearwardly thereof (XE). It has been found that XE equal to zero gives optimum results; however, reasonable results can be achieved by having XE about equal to plus or minus 12 percent of AW. That is, as explained previously when the plane swept out by the rear edge is coextensive with the surface of the radial flat or within the tolerance set forth. By changing the orientation of the fan with respect to the fan exit section it is also possible to direct the air stream, straight back, at an angle off radial, etc., depending on preference and need.
Considering the air flow patterns shown in Figure 2 it is necessary to cut off -the air flow, figura-tively shown as number 51, without the interruption of the generally radially flow pattern shown as number 53. As was previously stated the drawing of air in the hub region has a substantial detrimental effect on the efficiency o~
the fan. However, if a barrier is employed it should be positioned to cut off hub recirculation and not disrupt the flow pattern in the tip regions.
Referring to Figure 1 and 3, an air recirculation barrier means 31 is shown positioned behind the fan blade means 28. As shown in Figure 1 barrier means 31 is in the form of a flat disk which ~ .~ _ 9 _ ~036~7 has an overall diameter about equal to that of the periphery of flange 44 of the shroud exit section 38. The barrier means is secured to frame means 12 by any suitable mode with a properly located opening for the fan drive shaft means 26.
It should be noted, however, barrier means or disk 31 could be mounted to the drive shaft 26 or in fact front portion means 37 of engine means 10 could be positioned and modified to perform the necessary function of preventing the recirculation of air in the hub region.
It has been determined that optimum performance of the cooling assembly so described can be achieved when barrier means 31 is positioned on a third vertical plane rear-wardly of the second plane containing the trailiny edge means 52 of fan means 28, a distance corresponding to about 15 percent of the diameter of the circle generated by the tips of the fan means 28, which is an axial distance less than one-half of the diameter of the generated circle. The diameter of the barrier need only be substantially equal to that of the periphery of flange 44 in order to prevent the drawing in of air from the rearward areas into the hub portion.
The location of such a barrier means on a third plane which is generally opposite and parallel with the second plane containing the trailing edge of fan means 28 has been found to effectively retard hub recirculation without detrimentally effecting air flow patterns in the tip regions. This result is shown in Figure 3 by the air flow pattern as characterized by the number 39.
The barrier means 31 also serves as a safety guard for preventing accidental entry of hands etc. into the area adjacent fan means 28.
Thus it is apparent that there has been provided in accordance with the invention a shroud exit means that fully satisfies the objects, aims, and advantages set forth above. While the invention has been described in . ~ .
~, ? 1 0 ~364~7 conjunction with specific embodiments thereof, it is evident that many alternatives, modifications, and variations will be apparent to those skilled in the art in light of the fore~oinq description. Accordingly, it is intended to e~hrace all such alternatives, modifica-tions, and variations as ~all within the spirit and broad scope of the appended claims.
;
A HEAT TRANSFER SYSTEM
SPECIFICATION
This invention relates to a cooling assembly and more particularly to a fan shroud, a contoured fan shroud exit section and a fan located therein which has an air obstruction barrier therebehind. Reference should be made to my copending Canadian applications Serial Numbers 184,880 and 184,881, both filed November 2, 1973.
Most vehicles in general used today are driven by internal combustion engines. These engines being heat produc-ing are for the most part water cooled, that is, the engine is jacketed for circulation of water which takes up the heat and subsequently transfers it to the atmosphere. The radiator is used for cooling the liquid circulating through the engine by dissipating the heat to an air stream. The air flowing through the radiator absorbs the heat and carries it out into the atmosphere. Different types of fan systems are used to achieve the necessary air velocity through the radiator.
That is, some fan assemblies draw air from the atmosphere through the radiator and back over the engine thereafter exiting to the atmosphere. This type of fan is known as an axial flow suction fan, drawing air axially through the radi-ator and discharging it into the engine compartment. Other fans work in the reversed manner, that is, they draw air from the engine compartment wherefrom it is blown forwardly through the radiator to achieve the necessary radiator cooling.
Under optimum conditions it is believed prior art fans normally employ only about 1/3 of the length of the fan blade for the movement of air through the heat exchanger. The outer 1/3 of the blade length or tip regions, pulls in air from behind the shroud and recirculates it. The inner 1/3 or, hub region, pulls in air from the rear which it thereafter dis-``` ~036~7 charges rearwardly. As a result of these conditions onlyabout the middle 1/3 of the fan blade is effective in moving a cooling stream of air past the heat exchanger.
It has been shown, see copending Canadian application Serial Number 184,880, that a contoured shroud exit reduces horsepower requirements and generated noise and hampers the recirculation of air in the tip regions of the fan blade because of the radial air discharge pattern generated thereby.
Employment of the contoured shroud exit thus, increases the amount of the fan blade which is effective for moving air past the heat exchanger means.
It is therefore an object of this invention to provide an air barrier means to prevent the drawing in and recircul-ation of air from behind the fan blade. Still another object of this invention is to provide an air barrier means which does not interfere with the flow of air in the tip regions of the fan blade. Yet another object of this invention is to provide an air barrier means which functions as a safety guard. Another object of this invention is to provide a cooling assembly wherein a majority of the length of fan blade is functioning to move air each past the heat exchanger.
Broadly, the invention attains that object with a heat exchange apparatus which comprises a generally upright radiator having air intake and air discharge faces, and a rotatable multi-bLaded, axial flow, suction-type fan having a hub positioned on one side of the radiator adjacent the air discharge face for drawing air through the radiator axially in a direction from the air intake face to the air discharge face with the air flow through the radiator having a major component parallel ... .. .
with respect to the rotational axis of the fan with the blades having an effective axial width (AW) measured axially along the rotational axis of the fan between a first plane and a second plane. The planes are axially spaced and parallel with respect to each other and disposed substantially normal to the rotational ~3~47 axis of the fan. The first and second planes extend radially, respectively, through points on the leadiny edges of the blades at the radial tip portions thereof and through points on the trailing edges of the blades at the radial tip portion thereof.
A shroud means having one axial end operatlvely connected to the radiator encircles the fan, with the shroud means being shaped and positioned with respect to the radiator and the blades of the fan whereby the major component of air stream discharged by the fan is in a direction perpendicular to the direction of the major component of the air stream entering the air intake face and flowing through the radiator, and the axial end of the shroud means remote from the axial end operatively connected to the radiator is defined by an annular, radiaily outwardly extending flat portion lying substantially in a plane disposed perpendicular to the rotational axis of the fan and being substantially coin-cident with one of the first and second planes. A means is posi-tioned axially on the side of the fan opposite the radiator for obstructing flow of air axially through the fan at the hub region thereof in an axial direction opposite the direction of the major component of air flow through the radiator, with the means lying substantially in a plane spaced and substantially parallel with respect to the plane in which the flat portion of the shroud means lies.
j In accordance with the preferred embodiment of this inven-tion a vehicle is provided having a liquid cooled internal com-bustion engine and a radiator cooling system for dissipating the heat produced. The radiator cooling system includes a standard radiator, an axial flow fan facing the radiator and having a plurality of angular blades whereby air is drawn rearwardly through the radiator. A shroud rearwardly extends from the back face of the radiator to channel air through the radiator and hamper the fan from drawing air which has not passed through or at least come in contact with the perforated heat exchanging .
1(~369~47 surfaces of the radiator. For the most part the shroud encloses the entire perforated heat exchanging rear area of the radiator.
A fan shroud exit means is also provided having secured to the backwardly extending portion of the fan shroud and extending rearwardly thereof as well as outwardly. The particular contour of this exit section in combination with an axial flow fan located therein, allows the air stream to be converged and directed generally radially away from the engine compartment. Situated behind the fan is an air barrier means which in combination with the shroud exit section forces the fan to draw air through the radiator. As is apparent this invention is also applicable to a stationary engine where it is desired to achieve a high degree of performance from the fan blades.
Other objects and advantages of the invention will become apparent upon reading the following detailed description and upon reference to the drawings, in which;
FIGURE 1 is a side elevation of an internal combustion engine showing the combination of my invention with a contoured shroud exit section attached to a vehicle;
FIGURE 2 is a ~ragmentary vertical section showing the relationship o the fan, the contoured exit section, and the air flow pattern without an air barrier; and FIG~RE 3 is a fragmentary vertical section showing the air flow pattern with an air barrier.
, While the invention will be described in connection with a preferred embodiment, it will be understood that it is not intended to limit the invention to that embodiment- On the contrary, it is intended to cover all alternatives, modifications and equivalents as may be included within the spirit and scope ,of this invention as defined by the appended claims.
Turning first to Figure 1 there is shown a conventional water cooled heat producing internal combustion engine means 10 forwardly carried on longitudinally extending parallel support means 12 of vehicle means 14.
.
, -5-~. .
~(33~ 7 As shown herein vehicle means 14 is a tractor, however, as will hereafter become more apparent this invention can be applied to any type of vehicle employing a heat generating internal combustion engine or any other portable or stationary device requiring an air moving fan. For-wardly mounted is a water cooling radiator means 16 employed to dissipate the engine generated heat. Water flows between the water jacket on the engine (not shown) ; and the radiator through a series of fluid communicating means 18 and 20. In this particular embodiment sheet metal means 22 encircles engine means 10 thereby forming the engine compartment area means 24.
Carried at the forward end of engine means 10 is a fan shaft means 26 whereby power is delivered to drive fan means 28 (Figure 2). As is apparent, the particular mode whereby power is transmitted thereto is not critical and belts and pulleys could also be employed. As employed here, fan means 28 is a rotatable suction fan positioned opposite the radiator means 16, and normall~ creating a 10w of air or drawing in a stream of cooling air rearwardly through the radiator with a subsequent axial discharge thereof. This axial flow of air is directed to the fan means by a shroud means 30. The particular shape of the forward section 32 is dependent upon the shape and design of the perforated heat exchanging design of the radiator. The nature of the connection bstween the leading edge of 32 and the rear face 34 of the radiator will be dependent upon the particular characteristics of these components, that is, some connections being provided with air gaps while others ~a36~47 are substantially sealed over the entire circumference of the enclosure. In the preferred form of this inven-tion the entire perforated area is substantially sealed against the passage of air from any other direction except through the radiator. From the forward edges the shroud means 30 (be it a taper transition as shown or a box type) converges rearwardly to a circular rear section 36. An air barrier means 31 is positioned rearwardly of the shroud exit section 38 as will be more fully hereafter discussed.
Referring now to Figure 2 wherein is more clearly shown a shroud exit means 38 extending rearwardly and outwardly from shroud edge 36. The connection between the shroud and the shroud exit can be achieved by any suitable means, however, it is desirable that such con-nection be relatively free of gaps or spaces which would allow the passage of air. Exit shroud means 38 includes a tubular means 40, an arcuated means portion 42 and a flat flange portion means 44. For the most part tubular means portion 40 forms the leading edge of the shroud exit means while arcuated means portion 42 still extend-ing generally rearwardly simultaneously extends outwardly around an arc the reference point of which is defined as point 46. That is, arcuated section 42 has a general bell-shaped appearance being a section of a transition surface or some approximation thereof. In the preferred embodiment arcuated section 42 is a section of a constant radius arch. Flat flange portion 44 forms the trailing edge of exit shroud means 38 and has a major plane per-pendicular to that of tubular section 40. For purposes - ~3~4~
of simplicity, tubular means 40 will be hereafter referred to as the cylindrical throat means, arcuated portion 42 will be referred to as the radial expanding means and flat flange portion 44 will be referred to as radial flat means. Overall the entire fan shroud exit means 38 has a horn-like configuration.
The fan means 28 is rotatingly carried adjacent said radiator means and operable to establish a flow of cooling air therethrough.
Fan means 28 includes a plurality of fan blade means 48 (only one shown) as is well known in the art. As shown in Figure 2 fan means 28 is surrounded by said contoured fan shroud exit section 38. The enclosure of the fan means 28 within shroud means 30 is such that a front plane struck out by the leading edge 50 is coextensive and passes through the leading section of throat means 40 and a rear plane struck out by trailing edge 52 is about coextensive and parallel with said radial flat portion 44. It should be noted, however, that there is a plus or minus error factor involved in both of these values of about 12 percent of AW. That is, the respective planes formed by the blade means can be within about 12 percent of optimum and still function satisfactorily within the scope of this invention. Thus, within this range the deflected air stream will still be substantially radial. And generally about the outer two/thirds of the blade means is efficiently moving air through the radiator means.
While a beneficial effect is achieved by spacing the fan blades 48 with respect to the contoured shroud means 38 within the afor`ementioned range, it has been determined that best results are obtained when the front or first vertical plane struck out by the leading edges 50 of the fan blades 48 pass through the juncture or merger between the entrance shroud means 32 and the cylindrical exit shroud section 40. Even more determinative on the result is the relationship between the so-called rear plane struck out by the trailing edges 52 of the fan blades 48 and the radial flat flange shroud portion 44. Best overall performance is achieved when the rear or second vertical plane and the radial flat flange shroud portion or section 44 lie in the same plane.
_ Q _ ~ 47 The following relationship exists between these parameters: RF = AW/3, CF = AW/3, and R = 2AW/3 where RF is the length of the radial flat portion 44, CF is the length of the cylindrical throat section 40 and R is a radius of the radial expanding section 42 or distance from the reference point to the transition surface and AW is the projected axial width of fan 28.
The amount or relation of the fan means 28 to the exit section means 38 is most conveniently expressed in terms of the amount of the fan which is exposed past the end of the shroud or projects rearwardly thereof (XE). It has been found that XE equal to zero gives optimum results; however, reasonable results can be achieved by having XE about equal to plus or minus 12 percent of AW. That is, as explained previously when the plane swept out by the rear edge is coextensive with the surface of the radial flat or within the tolerance set forth. By changing the orientation of the fan with respect to the fan exit section it is also possible to direct the air stream, straight back, at an angle off radial, etc., depending on preference and need.
Considering the air flow patterns shown in Figure 2 it is necessary to cut off -the air flow, figura-tively shown as number 51, without the interruption of the generally radially flow pattern shown as number 53. As was previously stated the drawing of air in the hub region has a substantial detrimental effect on the efficiency o~
the fan. However, if a barrier is employed it should be positioned to cut off hub recirculation and not disrupt the flow pattern in the tip regions.
Referring to Figure 1 and 3, an air recirculation barrier means 31 is shown positioned behind the fan blade means 28. As shown in Figure 1 barrier means 31 is in the form of a flat disk which ~ .~ _ 9 _ ~036~7 has an overall diameter about equal to that of the periphery of flange 44 of the shroud exit section 38. The barrier means is secured to frame means 12 by any suitable mode with a properly located opening for the fan drive shaft means 26.
It should be noted, however, barrier means or disk 31 could be mounted to the drive shaft 26 or in fact front portion means 37 of engine means 10 could be positioned and modified to perform the necessary function of preventing the recirculation of air in the hub region.
It has been determined that optimum performance of the cooling assembly so described can be achieved when barrier means 31 is positioned on a third vertical plane rear-wardly of the second plane containing the trailiny edge means 52 of fan means 28, a distance corresponding to about 15 percent of the diameter of the circle generated by the tips of the fan means 28, which is an axial distance less than one-half of the diameter of the generated circle. The diameter of the barrier need only be substantially equal to that of the periphery of flange 44 in order to prevent the drawing in of air from the rearward areas into the hub portion.
The location of such a barrier means on a third plane which is generally opposite and parallel with the second plane containing the trailing edge of fan means 28 has been found to effectively retard hub recirculation without detrimentally effecting air flow patterns in the tip regions. This result is shown in Figure 3 by the air flow pattern as characterized by the number 39.
The barrier means 31 also serves as a safety guard for preventing accidental entry of hands etc. into the area adjacent fan means 28.
Thus it is apparent that there has been provided in accordance with the invention a shroud exit means that fully satisfies the objects, aims, and advantages set forth above. While the invention has been described in . ~ .
~, ? 1 0 ~364~7 conjunction with specific embodiments thereof, it is evident that many alternatives, modifications, and variations will be apparent to those skilled in the art in light of the fore~oinq description. Accordingly, it is intended to e~hrace all such alternatives, modifica-tions, and variations as ~all within the spirit and broad scope of the appended claims.
;
Claims (3)
1. A heat exchange apparatus comprising:
a generally upright radiator having air intake and air discharge faces;
a rotatable multi-bladed, axial flow, suction-type fan having a hub positioned on one side of said radiator adjacent said air discharge face for drawing air through said radiator axially in a direction from said air intake face to said air discharge face, said air flow through said radiator having a major component parallel with respect to the rotational axis of the fan, said blades having an effective axial width (AW) measured axially along the rotational axis of the fan between a first plane and a second plane, said planes being axially spaced and parallel with respect to each other and disposed substantially normal to the rotational axis of the fan, said first and second planes extending radially, respectively, through points on the leading edges of the blades at the radial tip portions thereof and through points on the trailing edges of the blades at the radial tip portion thereof;
shroud means having one axial end operatively connected to said radiator and encircling said fan, said shroud means being shaped and positioned with respect to said radiator and the blades of said fan whereby the major component of air stream discharged by the fan is in a direction perpendicular to the direction of the major component of the air stream entering the air intake face and flowing through said radiator, the axial end of said shroud means remote from said axial end operatively connected to said radiator being defined by an annular, radially outwardly extending flat portion lying substantially in a plane disposed perpendicular to the rotational axis of said fan and being substantially coincident with one of said first and second planes; and means axially positioned on the side of said fan opposite said radiator for obstructing flow of air axially through the fan at the hub region thereof in an axial direction opposite the direction of said major component of air flow through said radiator, said means lying substantially in a plane spaced and substantially parallel with respect to said plane in which said flat portion of said shroud means lies.
a generally upright radiator having air intake and air discharge faces;
a rotatable multi-bladed, axial flow, suction-type fan having a hub positioned on one side of said radiator adjacent said air discharge face for drawing air through said radiator axially in a direction from said air intake face to said air discharge face, said air flow through said radiator having a major component parallel with respect to the rotational axis of the fan, said blades having an effective axial width (AW) measured axially along the rotational axis of the fan between a first plane and a second plane, said planes being axially spaced and parallel with respect to each other and disposed substantially normal to the rotational axis of the fan, said first and second planes extending radially, respectively, through points on the leading edges of the blades at the radial tip portions thereof and through points on the trailing edges of the blades at the radial tip portion thereof;
shroud means having one axial end operatively connected to said radiator and encircling said fan, said shroud means being shaped and positioned with respect to said radiator and the blades of said fan whereby the major component of air stream discharged by the fan is in a direction perpendicular to the direction of the major component of the air stream entering the air intake face and flowing through said radiator, the axial end of said shroud means remote from said axial end operatively connected to said radiator being defined by an annular, radially outwardly extending flat portion lying substantially in a plane disposed perpendicular to the rotational axis of said fan and being substantially coincident with one of said first and second planes; and means axially positioned on the side of said fan opposite said radiator for obstructing flow of air axially through the fan at the hub region thereof in an axial direction opposite the direction of said major component of air flow through said radiator, said means lying substantially in a plane spaced and substantially parallel with respect to said plane in which said flat portion of said shroud means lies.
2. A heat exchange apparatus as set forth in Claim 1, wherein:
said means positioned on the side of said fan opposite said radiator for obstructing flow of air axially through the fan at the hub region thereof in an axial direction opposite the direction of said major component of air flow through said radiator includes a generally circular, substantially flat disk and is spaced from said plane in which said flat portion of said shroud means lies a distance along the rotational axis of said fan about 15 percent of the diameter of the fan.
said means positioned on the side of said fan opposite said radiator for obstructing flow of air axially through the fan at the hub region thereof in an axial direction opposite the direction of said major component of air flow through said radiator includes a generally circular, substantially flat disk and is spaced from said plane in which said flat portion of said shroud means lies a distance along the rotational axis of said fan about 15 percent of the diameter of the fan.
3. A heat exchange apparatus as set forth in Claim 2, wherein:
the radially outermost periphery of said radial flat portion being defined by a circle having a diameter substantially the same as the diameter of said flat disk.
the radially outermost periphery of said radial flat portion being defined by a circle having a diameter substantially the same as the diameter of said flat disk.
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US44719274A | 1974-03-01 | 1974-03-01 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1036447A true CA1036447A (en) | 1978-08-15 |
Family
ID=23775359
Family Applications (2)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA213,118A Expired CA1036447A (en) | 1974-03-01 | 1974-11-06 | Recirculation barrier for a heat transfer system |
| CA290,975A Expired CA1040035A (en) | 1974-03-01 | 1977-11-16 | Recirculation barrier for a heat transfer system |
Family Applications After (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA290,975A Expired CA1040035A (en) | 1974-03-01 | 1977-11-16 | Recirculation barrier for a heat transfer system |
Country Status (10)
| Country | Link |
|---|---|
| JP (1) | JPS50121634A (en) |
| AU (1) | AU474370B2 (en) |
| BR (1) | BR7501203A (en) |
| CA (2) | CA1036447A (en) |
| DE (1) | DE2505563B2 (en) |
| FR (1) | FR2262607B2 (en) |
| GB (1) | GB1471503A (en) |
| IT (1) | IT1026476B (en) |
| NL (1) | NL156213B (en) |
| SE (1) | SE409485B (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103717908A (en) * | 2011-05-25 | 2014-04-09 | 罗伯特·博世有限公司 | Fan duct with downstream edge shaped for noise reduction |
Families Citing this family (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS57112025U (en) * | 1980-12-27 | 1982-07-10 | ||
| DE3447195A1 (en) * | 1984-12-22 | 1986-07-03 | M A N Nutzfahrzeuge GmbH, 8000 München | COOLING DEVICE WITH AXIAL FAN IN CAPSULE DESIGN |
| DE3503220C1 (en) * | 1985-01-31 | 1986-07-03 | Daimler-Benz Ag, 7000 Stuttgart | Radiator frame arranged on the cooler of a liquid-cooled internal combustion engine |
| US5105639A (en) * | 1989-02-23 | 1992-04-21 | Spiro America Inc. | Apparatus for forming spiral pipe |
| DE4137703C1 (en) * | 1991-11-15 | 1992-12-10 | Mercedes-Benz Aktiengesellschaft, 7000 Stuttgart, De | |
| EP0947706B1 (en) * | 1997-09-19 | 2006-11-22 | Hitachi Construction Machinery Co., Ltd. | Cooling apparatus for construction machinery and construction machinery |
| US6827547B2 (en) | 2003-01-29 | 2004-12-07 | Borgwarner Inc. | Engine cooling fan having improved airflow characteristics |
| USD805107S1 (en) | 2016-12-02 | 2017-12-12 | U.S. Farathane Corporation | Engine fan shroud |
| CN111648854A (en) * | 2020-06-09 | 2020-09-11 | 安徽江淮银联重型工程机械有限公司 | Combined radiator for large forklift |
-
1974
- 1974-11-06 CA CA213,118A patent/CA1036447A/en not_active Expired
- 1974-12-05 AU AU76119/74A patent/AU474370B2/en not_active Expired
- 1974-12-18 NL NL7416536.A patent/NL156213B/en not_active IP Right Cessation
-
1975
- 1975-01-14 GB GB153675A patent/GB1471503A/en not_active Expired
- 1975-01-27 IT IT47856/75A patent/IT1026476B/en active
- 1975-02-10 DE DE19752505563 patent/DE2505563B2/en not_active Ceased
- 1975-02-27 SE SE7502245A patent/SE409485B/en unknown
- 1975-02-28 BR BR1203/75A patent/BR7501203A/en unknown
- 1975-02-28 FR FR7506250A patent/FR2262607B2/fr not_active Expired
- 1975-03-01 JP JP50025536A patent/JPS50121634A/ja active Pending
-
1977
- 1977-11-16 CA CA290,975A patent/CA1040035A/en not_active Expired
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103717908A (en) * | 2011-05-25 | 2014-04-09 | 罗伯特·博世有限公司 | Fan duct with downstream edge shaped for noise reduction |
Also Published As
| Publication number | Publication date |
|---|---|
| IT1026476B (en) | 1978-09-20 |
| DE2505563A1 (en) | 1975-09-04 |
| FR2262607A2 (en) | 1975-09-26 |
| JPS50121634A (en) | 1975-09-23 |
| GB1471503A (en) | 1977-04-27 |
| AU7611974A (en) | 1976-06-10 |
| NL7416536A (en) | 1975-09-03 |
| SE409485B (en) | 1979-08-20 |
| SE7502245L (en) | 1975-09-02 |
| AU474370B2 (en) | 1976-07-22 |
| FR2262607B2 (en) | 1979-10-19 |
| DE2505563B2 (en) | 1976-06-16 |
| BR7501203A (en) | 1975-12-09 |
| NL156213B (en) | 1978-03-15 |
| CA1040035A (en) | 1978-10-10 |
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