HK1135161B - Sirocco fan and air conditioner - Google Patents

Description

Sirocco fan and air conditioner

Technical Field

The present invention relates to a sirocco fan having reduced noise and improved air blowing characteristics, and an air conditioner provided with the sirocco fan.

Background

A sirocco fan has been frequently used in air conditioners, air cleaners, and the like. The sirocco fan includes a scroll-shaped scroll and a plurality of forward blades (blades) arranged in a cylindrical shape and rotatably disposed in the scroll. As an air conditioner having such a sirocco fan, for example, a sirocco fan of a window side air conditioner disclosed in patent document 1 is known. The sirocco fan of the window side air conditioner includes a housing and a plurality of blades arranged in the housing at a certain interval, wherein the blades have an outlet angle of 125-137 degrees, an inlet angle of 58-63 degrees, a blade disc area ratio of 0.75-0.85, an inner-outer diameter ratio of 0.82-0.86, and a maximum bending position of 0.3-0.4. By forming the blade form as described above, even if the rotation speed is increased while maintaining the air blowing amount, noise is not increased.

Patent document 1: japanese patent laid-open No. 2001-323895 (claim 1, FIGS. 1 to 3)

However, in an air conditioner equipped with a conventional sirocco fan, since the output air volume of the sirocco fan at a predetermined noise level is small and the heat exchanger performance is degraded, the load on the compressor is increased and COP (coefficient of performance) is degraded, and further, in order to suppress the COP degradation, the noise level is increased when the output air volume of the sirocco fan is increased, which causes a problem of discomfort to the user.

Disclosure of Invention

The present invention has been made in view of the above-described problems, and an object of the present invention is to provide a sirocco fan that can increase the air volume when a predetermined noise is generated, in other words, can reduce the noise level and the number of revolutions when a predetermined air volume is generated, and an air conditioner including the sirocco fan.

The sirocco fan of the present invention has a scroll, and a plurality of blades arranged in a cylindrical shape rotatably in the scroll, wherein: the diameter of the fan is D, the maximum bending height is H, the chord length is L, the radius of the front edge of the inner circumference side of the blade is R, and the inlet angle is beta₁An exit angle of beta₂When the ratio of H/L is more than or equal to 0.18 and less than or equal to 0.26, R/L is less than or equal to 0.11, beta is more than or equal to 100 degrees₁≤130°，26°≤β₂≤32°。

ADVANTAGEOUS EFFECTS OF INVENTION

According to the present invention, the blade shape of the sirocco fan is defined by a fan diameter D, a maximum bending height H, a chord length L, a radius of a leading edge on the inner peripheral side of the blade R, an entrance angle beta₁The exit angle is beta₂When the ratio of H/L is more than or equal to 0.18 and less than or equal to 0.26, R/L is less than or equal to 0.11, beta is more than or equal to 100 degrees₁≤130°，26°≤β₂32 DEG or less, so that the air quantity in the specified noise can be increased, and in addition, the air quantity in the specified noise can be increasedIn addition, in the case of an air conditioner, COP can be improved.

Drawings

Fig. 1 is a schematic plan view (a) and a schematic side view (b) showing an internal configuration of an air conditioning indoor unit having a sirocco fan according to embodiment 1 of the present invention. Fig. 2 is a parameter explanatory diagram showing a blade shape of the sirocco fan in embodiment 1. Fig. 3 is a diagram showing the blade shape of the sirocco fan in embodiment 1. Fig. 4 is a diagram comparing the blade shape of the sirocco fan in embodiment 1 with the conventional blade shape. Fig. 5 is a diagram showing the blade shape of the sirocco fan in embodiments 1 and 2. Fig. 6 is a diagram showing a relative speed distribution of the sirocco fan in embodiment 1. Fig. 7 is a diagram showing a relative speed distribution of the sirocco fan in embodiment 2.

Description of the symbols

1 sirocco fan, 2 fan motor, 3 heat exchanger, 4 suction inlet, 5 blow-out outlet, 6 scroll, 7 rotation axis, 8 blades, 9 bend line, 10 indoor unit, 11 straight line (chord length L), 12 perpendicular line, 13 inner circumference tangent line, 14 bend line tangent line, 15 outer circumference tangent line, 16 bend line tangent line.

Detailed Description

Embodiments of the present invention will be described below with reference to the drawings.

Embodiment 1 fig. 1 is a schematic plan view (a) and a schematic side view (b) showing an internal configuration of an indoor unit of an air conditioner having a sirocco fan according to embodiment 1 of the present invention. In fig. 1, reference numeral 10 denotes an indoor unit constituting an indoor air conditioner, and includes a pair of sirocco fans 1, a fan motor 2 that rotationally drives the sirocco fans 1, and a heat exchanger 3 that exchanges heat with air blown from the sirocco fans 1. The sirocco fan 1 includes a scroll-shaped scroll 6 and a plurality of blades arranged in a cylindrical shape rotatably in the scroll 6. In the figure, reference numeral 4 denotes an air inlet, reference numeral 5 denotes a cold air or warm air outlet, and reference numeral 7 denotes a rotary shaft of the fan motor 2.

The indoor unit 10 includes a refrigeration circuit for a refrigerant including a compressor, a condenser, an expansion valve, and an evaporator, which are not shown, and performs indoor cooling, heating, and the like. In addition, as an example of the technical specification in embodiment 1, the fan diameter of the sirocco fan 1 is160mm in width, 190mm in width, 40 fins in number, and 12 heat transfer tubes with a row pitch of 12.7mm, a segment pitch of 20.4mm, a heat transfer tube axial length of 700mm, and a draft resistance Δ P1 of 23.1V^1.3[Pa](V: speed [ m/s ]]). In addition, the depth of the indoor unit 10 is 680mm, the height is 210mm, and the width is 960 mm.

The indoor air is sucked in from the suction port 4 of the indoor unit 10 and is further sucked in the axial direction from the suction port of the scroll 6. The fan motor 2 rotates the cylindrical blade row in the scroll 6, and the air having dynamic pressure and static pressure applied thereto by the blade row is blown out from the outlet opening in the air passage of the indoor unit 10, exchanges heat with the heat exchanger 3 provided in the air passage, and is formed into cold air or warm air, and is blown out from the air outlet 5 into the room.

Fig. 2 is a parameter explanatory diagram showing a blade shape of the sirocco fan, fig. 3 is a diagram showing a blade shape of the sirocco fan according to embodiment 1, and fig. 4 is a comparative diagram showing a conventional blade shape superimposed on fig. 3.

The flow rate of the sirocco fan 1 at a predetermined noise value is determined by setting the fan diameter of the sirocco fan 1 to D, the chord length to L, the maximum bending height to H, the radius of the leading edge on the inner peripheral side of the blade to R, and the inlet angle to β₁An exit angle of beta₂When the measured value is D, L, H, beta₁、β₂And R is determined. Diameter D of fan and inner periphery of bladeThe radius R is not shown. Here, the above parameters are defined as follows. The fan diameter D is the diameter of the outer circumference of the blades 8 of the sirocco fan 1. The chord length L is the length of a straight line 11 connecting the inner peripheral end 9a and the outer peripheral end 9b of the bent line 9 of the blade 8. The maximum bending height H is the maximum length of the perpendicular 12 from the straight line 11 to the bending line 9 of the blade 8. Entrance angle beta₁Is an angle formed by an inner peripheral tangent 13 at an inner peripheral end 9a of a bending line 9 of the blade 8 and a bending line tangent 14. Angle of exit beta₂Is the angle formed by the outer peripheral tangent 15 at the outer peripheral end 9b of the bend line 9 of the blade 8 and the bend line tangent 16. The incident angle α is an angle formed by a curved line tangent 14 at the inner circumferential end 9a of the curved line 9 of the blade 8 and the inflow direction of the wind. The radius R of the blade inner circumference side front edge is the radius of the circular arc portion formed at the front edge of the blade 8.

On the other hand, when the conventional sirocco fan is denoted by reference numeral 100, the sirocco fan 100 has a disadvantage that the air volume at the time of predetermined noise is smaller than that of the sirocco fan 1. This is due to the small H/L, large R/L, beta₁、β₂The air volume at the time of the predetermined noise becomes small due to, for example, an inappropriate angle. As a result, when the heat exchanger is mounted on the indoor unit 10, the performance of the heat exchanger 3 is reduced, the load on the compressor is increased, and the COP is reduced.

As described above, in the case of the indoor unit having the sirocco fan 100 mounted thereon, since the air volume at the time of a predetermined noise becomes small and the performance of the heat exchanger 3 is degraded, when a predetermined air conditioning capacity is obtained at the time of a predetermined noise, the refrigerant temperature needs to be lowered more than necessary in the case of performing a cooling operation, and in the case of performing a heating operation, the refrigerant temperature needs to be raised more than necessary, and the temperature difference between the refrigerant temperature and the indoor temperature needs to be increased, which causes a problem that the load on the compressor becomes large and the COP decreases.

Table 1 shows H/L, R/L, β ratios of the sirocco fan 1A of embodiment 1 and the conventional sirocco fan 100₁、β₂The value of (c). The value of L/D was 0.17.

[ Table 1]TABLE 1 shape parameters of the blades

	Sirocco fan 1A	Sirocco fan 100
			H/L	0.22	0.28
R/L	0.16	0.16
			β1	100°	100°
β2	43°	43°

Table 2 shows that the sirocco fan 1A and the sirocco fan 100 are mounted on the indoor unit 10 and that the blowing air volume is 16m³Noise value at/min, rotational speed. The conditions other than the sirocco fan are the same.

[ Table 2 ]]Table 216m³Noise value and rotational speed at/min

	Sirocco fan 1A	Sirocco fan 100
			Noise value dB	46.5	47.2
Rotational speed rpm	1101	1127

As shown in tables 1 and 2, the noise value and the number of revolutions can be reduced by setting H/L to 0.22.

Table 3 shows the sirocco fan 1B according to embodiment 1 and the conventional fansH/L, L/D, R/L, beta of sirocco fan 100₁、β₂The value of (c).

[ Table 3 ]]TABLE 3 shape parameters of the blade

	Sirocco fan 1B	Sirocco fan 100
			H/L	0.28	0.28
R/L	0.11	0.16

β1	125°	125°
			β2	47°	47°

Table 4 shows that the sirocco fan 1B and the sirocco fan 100 are mounted on the indoor unit 10 and that the blowing air volume is 16m³Noise value at/min, rotational speed. The conditions other than the sirocco fan are the same.

[ Table 4 ]]Table 416m³Noise value and rotational speed at/min

	Sirocco fan 1B	Sirocco fan 100
			Noise value dB	46.1	47.2
Rotational speed rpm	1088	1127

As shown in tables 3 and 4, the noise value and the number of revolutions can be reduced by setting R/L to 0.11.

Table 5 shows H/L, R/L, β ratios of the sirocco fan 1C of embodiment 1 and the conventional sirocco fan 100₁、β₂The value of (c).

[ Table 5 ]]TABLE 5 shape parameters of the blades

	Sirocco fan 1C	Sirocco fan 100
			H/L	0.28	0.28
R/L	0.16	0.16
			β1	110°	125°
β2	47°	47°

Table 6 shows that the sirocco fan 1C and the sirocco fan 100 are mounted on the indoor unit 10 and that the blowing air volume is 16m³Noise value at/min, rotational speed. Conditions other than sirocco fans being completeAs such.

[ Table 6 ]]Table 616m³Noise value and rotational speed at/min

	Sirocco fan 1C	Sirocco fan 100
			Noise value dB	46.3	47.2
Rotational speed rpm	1115	1127

As shown in tables 5 and 6, the value of beta is set₁The noise value and the rotating speed can be reduced by 110 degrees.

Table 7 shows H/L, R/L, β ratios of the sirocco fan 1D according to embodiment 1 and the conventional sirocco fan 100₁、β₂The value of (c).

[ Table 7 ]]TABLE 7 shape parameters of the blades

	Sirocco fan 1D	Sirocco fan 100
			H/L	0.28	0.28

R/L	0.16	0.16
			β1	125°	125°
β2	29°	47°

Table 8 shows that the sirocco fan 1D and the sirocco fan 100 are mounted on the indoor unit 10 and that the air volume is 16m³Noise value at/min, rotational speed. The conditions other than the sirocco fan are the same.

[ Table 8 ]]TABLE 816m³Noise value and rotational speed at/min

	Sirocco fan 1D	Sirocco fan 100
			Noise value dB	46.4	47.2
Rotational speed rpm	1113	1127

As shown in tables 7 and 8, the value of beta is determined₂The noise value and the rotating speed can be reduced by 29 degrees.

In table 9, H/L is 0.22, R/L is 0.11, β₁＝110°、β₂When the sirocco fan 1 is mounted on the indoor unit 10 at 29 °, the blowing air volume is 16m³Noise value at/min, rotational speed.

[ Table 9 ]]Table 916m³Noise value and rotational speed at/min

	Sirocco fan 1
		Noise value dB	45.3
Rotational speed rpm	1088

As shown in Table 9, the optimum combinations of H/L, R/L and beta₁、β₂The noise value and the rotation speed are both minimized.

The following description will discuss the case where H/L is 0.22, R/L is 0.11, and β₁＝110°、β₂The reason why the noise value and the rotation speed are reduced at 29 °.

When the H/L ratio is larger than 0.26, the blade bends largely, and the wind separates from the blade surface on the negative pressure surface side, so that the stall occurs, which causes an increase in noise level and rotational speed. On the other hand, when the H/L ratio is smaller than 0.18, the bending of the blade becomes small, and the lift force of the blade decreases, which causes an increase in noise level and rotational speed. When the R/L ratio is larger than 0.11, the stagnation pressure increases at the leading edge of the blade, and the dynamic pressure decreases, so that the air volume decreases, which causes an increase in the noise value and the rotational speed. At beta₁When the angle is larger than 130 °, the inflow area of the inflow portion between the blades decreases, which causes an increase in noise level and rotational speed. On the other hand, if beta₁When the angle is smaller than 100 °, the angle of incidence α of the blade increases, which causes the stall, and increases the noise value and the rotational speed. If beta is₂If the angle is larger than 32 °, the bending of the blade becomes small, and therefore, the lift force becomes small, which causes an increase in noise value and rotational speed. On the other hand, if beta₂When the angle is smaller than 26 °, the flow-out area of the inter-blade flow-out portion decreases, and therefore the speed of the inter-blade flow-out portion increases. Since the flow between the blades of the sirocco fan is in a state of being stalled to some extent, if the speed of the flow-out portion between the blades increases, the flow-out portion is attached to the leading edgeThe near stalled flow reattaches near the trailing edge. If reattachment occurs, static pressure fluctuation on the blade surface becomes large, which causes noise to increase.

Embodiment 2 describes in embodiment 1 that H/L is 0.22, R/L is 0.11, and β₁＝110°、β₂In the sirocco fan 1 of 29 °, as shown in fig. 5, the sirocco fan on the negative pressure surface side from which the leading edge is substantially linearly cut is 1X. The front edge of the sirocco fan 1 is shaped to be a semicircular arc.

Table 10 shows that the indoor unit 10 is equipped with the sirocco fan 1 and the sirocco fan 1X, and the blowing air volume is 16m³Noise value at/min, rotational speed. The conditions other than the sirocco fan are the same.

[ Table 10 ]]TABLE 1016m³Noise value and rotational speed at/min

	Sirocco fan 1X	Sirocco fan 1
			Noise value dB	45.3	45.8
Rotational speed rpm	1088	1103

As shown in table 10, when the negative pressure surface side of the front edge of the sirocco fan having the semicircular arc shape is cut, the noise value and the number of rotations can be reduced.

The reason will be described below. The relative velocity distribution in the fan near the main plate at 1100rpm is shown in FIGS. 6 and 7, and the static pressure (1100rpm, air volume 8 m) at the time of operating the fan alone is shown in Table 11³In/min). Comparing the relative velocity distribution in the fan of the sirocco fan 1 shown in fig. 6 and the sirocco fan 1X having the negative pressure surface side with the leading edge cut away shown in fig. 7, it can be seen that one of the sirocco fans 1X is presentThe velocity distribution near the leading edge on the negative pressure surface side is large. This is because the speed of the leading edge on the negative pressure surface side, where wind is likely to flow originally, is increased by cutting the negative pressure surface side, and as shown in table 10, the rotational speed is decreased, and the noise value is decreased. As can be seen from the static pressures shown in table 11, the sirocco fan 1X with the front edge cut on the negative pressure surface side can obtain the highest static pressure at the same rotation speed and the same air volume, and the effect of facilitating the flow of the outlet air is exhibited by cutting the front edge on the negative pressure surface side.

[ Table 11]TABLE 111100rpm, 8m³Static pressure at/min

	Sirocco fan 1X	Sirocco fan 1
			Static pressure Pa	61.3	60.2

Claims (3)

1. A sirocco fan having a scroll and a plurality of blades arranged in a cylindrical shape and rotatably disposed in the scroll, characterized in that:

the diameter of the fan is D, the maximum bending height is H, the chord length of the blade is L, the radius of the front edge of the inner circumference side of the blade is R, and the inlet angle of the blade is beta₁The outlet angle of the blade is beta₂When the ratio of H/L is more than or equal to 0.18 and less than or equal to 0.26, R/L is less than or equal to 0.11, beta is more than or equal to 100 degrees₁≤130°，26°≤β₂≤32°，

The fan diameter D is the diameter of the outer circumference of the blade (8) of the sirocco fan (1), the maximum bending height H is the maximum length of a perpendicular line (12) from a straight line (11) to a bending line (9) of the blade (8), and the straight line (11) is a straight line connecting the inner circumferential end (9a) and the outer circumferential end (9b) of the bending line (9) of the blade (8).

2. The sirocco fan of claim 1, wherein: the shape of the inner peripheral side leading edge of the blade is a shape in which the negative pressure surface side of the blade is substantially linearly cut off from a substantially semicircular arc shape.

3. An air conditioning apparatus, characterized in that: having a sirocco fan according to claim 1 or 2.