JPWO2010004628A1 - Sirocco fan and air conditioner using the same - Google Patents

Abstract

Provided are a sirocco fan and an air conditioner using the sirocco fan that reduce noise generated when a predetermined amount of blown air is supplied. In the sirocco fan 100 according to the present invention, the suction port 2a is formed on the extension line of the rotation center of the fan 1 and is formed on both side surfaces of the scroll casing 2, and the ventilation resistance in the air passage 2c is P [ Pa], the amount of air taken in from the suction port 2a is Q [m 3 / min], the width in the rotation axis direction of the fan 1 is L [mm], k is a constant, and the height of the scroll casing 2 is H = 246k [ mm], P / Q2 is a loss factor ξ [Pa / (m3 / min) 2], and f (k4ξ) = 0.34947 (k4ξ) 2 in the range of 0.1 ≦ k4ξ ≦ 0.4. -1.0554 (k4ξ) +1.8, and 0.75f (k4ξ) ≦ L / H ≦ f (k4ξ).

Description

  The present invention relates to a sirocco fan and an air conditioner using the sirocco fan, and more particularly to a sirocco fan that reduces generated noise and an air conditioner using the sirocco fan.

  Conventionally, there is a sirocco fan which is a multi-blade centrifugal fan having a cylindrical shape and capable of blowing a wide belt-like wind into an air-conditioning target area. This sirocco fan is often used for an indoor unit, a dehumidifier, an air purifier, and the like constituting an air conditioner. Such a sirocco fan is generally configured by arranging a plurality of elongated blades on a circumference and accommodating a fan having a cylindrical shape as a whole in a scroll casing in which a suction port and a blowout port are formed. The And the sirocco fan takes in air into the inside from a suction inlet, and blows off the taken-in air to the air-conditioning object area from the blower outlet side.

  As such, “comprising a plurality of multi-blade centrifugal fan units connected along the same rotation axis with a space between each other, and a casing containing the plurality of connected multi-blade centrifugal fan units, The casing forms a blowing flow path for blowing air discharged from the plurality of multiblade centrifugal fan units to the outside, and the blowing flow path is continuous with respect to the plurality of multiblade centrifugal fan units. A multi-blade fan that is a common flow path ”has been proposed (see, for example, Patent Document 1).

Japanese Patent Laid-Open No. 11-324984 (5th page, FIG. 7-8)

  In the conventional multiblade fan, there is a problem that the loss factor of the operating point is small, and when the operating point is on the open side of the surging area, the fan width is short and the noise generated at a predetermined air volume becomes large. It was. That is, in such a sirocco fan, when a predetermined amount of blown air is supplied to the air-conditioning target area, the sound generated from the fan becomes loud and is transmitted as noise to the air-conditioning target area, which is uncomfortable for the user. There was to give. Further, when the predetermined noise value is lowered, the amount of air blown from the sirocco fan is reduced, and when the amount of blown air is increased, the noise value increases, and it is difficult to achieve an appropriate balance between the amount of blown air and the generation of sound. There was also a problem. In addition, when the fan width is short and the loss factor is small, there is a problem that the fan diameter must be increased unnecessarily in order to reduce noise. Furthermore, when such a sirocco fan is used for an air conditioner, if the fan width is short, and there is a heat exchanger on the downstream side of the fan, the speed distribution in the width direction of the heat exchanger is uneven and the heat exchanger There was also a problem that the heat transfer performance deteriorated and the power consumption of the compressor increased. Another problem is that the relationship between the loss factor and the fan width is unclear.

  The present invention has been made to solve the above-described problem, and provides a sirocco fan that reduces noise generated when a predetermined amount of blown air is supplied and an air conditioner using the sirocco fan. It is an object.

A sirocco fan according to the present invention is housed in the scroll casing having a suction port for taking in air, a blowout port for blowing out air, a wind passage from the suction port to the blowout port, and the scroll casing. A fan that takes in air from the suction port by rotating and blows out air from the blower port, and a bell mouth attached to the suction port of the scroll casing, wherein the suction port is a rotation center of the fan , Which is formed on both side surfaces of the scroll casing, the ventilation resistance in the air passage is P [Pa], and the amount of air taken in from the suction port is Q [m ³ / min] The width of the fan in the rotation axis direction is L [mm], k is a constant, and the height of the scroll casing is H = 246 k [ m], when the P / Q ² the loss coefficient ^{ξ [Pa / (m 3 /} min) 2], in the range of ^{0.1 ≦ k 4 ξ ≦ 0.4,} f (k 4 ξ) = 0 34947 (k ⁴ ξ) ² −1.0554 (k ⁴ ξ) +1.8, and 0.75 f (k ⁴ ξ) ≦ L / H ≦ f (k ⁴ ξ).

A sirocco fan according to the present invention is housed in the scroll casing having a suction port for taking in air, a blowout port for blowing out air, a wind passage from the suction port to the blowout port, and the scroll casing. A fan that takes in air from the suction port by rotating and blows out air from the blower port, and a bell mouth attached to the suction port of the scroll casing, wherein the suction port is a rotation center of the fan Is an extension line of the scroll casing and is formed on one side surface of the scroll casing, the ventilation resistance in the air passage is P [Pa], and the amount of air taken in from the suction port is Q [m ³ / min]. The width of the fan in the rotation axis direction is L [mm], k is a constant, and the height of the scroll casing is H = 246 k [ m], when the P / Q ² the loss coefficient ^{ξ [Pa / (m 3 /} min) 2], in the range of ^{0.1 ≦ k 4 ξ ≦ 0.4,} g (k 4 ξ) = 1 .39788 (k ⁴ ξ) ² −2.1108 (k ⁴ ξ) +1.8, and 1.5 g (k ⁴ ξ) ≦ L / H ≦ 2 g (k ⁴ ξ).

  An air conditioner according to the present invention is characterized by using the above-described sirocco fan.

  According to the sirocco fan according to the present invention, it is possible to achieve a balance between the air blown air volume and the noise only by determining the fan width based on a predetermined formula so that the operating point of the fan falls within the predetermined range. The sound generated when supplying a predetermined amount of blown air can be effectively reduced.

It is the see-through | perspective perspective view which saw through and showed the inside of the sirocco fan which concerns on embodiment of this invention. It is the perspective view which showed the whole fan shape. It is sectional drawing which shows the schematic longitudinal cross-sectional structure of a sirocco fan. It is a graph showing the PQ characteristic and Ks-Q characteristic of a sirocco fan. It is a graph showing the relationship between L ₀ / H ₀ and the loss factor xi] ₀ of the sirocco fan. It is a graph showing the PQ characteristic and Ks-Q characteristic of a sirocco fan when passing through the operating point A. It is a graph showing the relationship between the air volume between blade | wings for every blade blade of a fan, and the position of a blade plate. It is a schematic sectional drawing which shows the longitudinal cross-sectional structure of a bellmouth. It is a perspective view of the sirocco fan which showed the area | region (alpha) of bellmouth. It is an enlarged view of the region α showing the rms value of the static pressure fluctuation on the wall surface of the region α without a step. It is an enlarged view of the region α showing the rms value of the static pressure fluctuation on the wall surface of the region α with a step. It is a longitudinal cross-sectional view which shows schematic sectional structure of a sirocco fan. It is a see-through | perspective perspective view which shows a sirocco fan transparently. It is a graph showing the PQ characteristic of a sirocco fan when passing through an operating point B. It is the top view which showed the schematic whole structure of the ceiling-suspended indoor unit carrying a sirocco fan. It is sectional drawing which showed the longitudinal cross-section structure of the ceiling-suspended indoor unit. It is a table | surface which shows the noise value in a ceiling suspended indoor unit. It is a schematic block diagram which shows schematic structure of the air conditioning apparatus which concerns on Embodiment 2 of this invention.

Explanation of symbols

  1 fan, 2 scroll casing, 2a inlet, 2b outlet, 2b1 tongue, 2c air passage, 3 bell mouth, 4 tongue, 5 suction space, 100 sirocco fan, 110 ceiling suspended indoor unit, 150 air conditioner, 151 compressor, 152 condensing heat exchanger, 153 expansion device, 154 evaporating heat exchanger.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
Embodiment 1
FIG. 1 is a see-through perspective view showing the inside of a sirocco fan 100 according to Embodiment 1 of the present invention. FIG. 2 is a perspective view showing the overall shape of the fan 1. FIG. 3 is a schematic longitudinal sectional view showing a sectional configuration of the sirocco fan 100. The overall configuration of the sirocco fan 100 will be described with reference to FIGS. The sirocco fan 100 is used for an indoor unit, a dehumidifier, an air purifier, or the like constituting an air conditioner such as an air conditioner or a dehumidifier. In addition, in the following drawings including FIG. 1, the relationship of the size of each component may be different from the actual one.

  As shown in FIG. 1, a sirocco fan 100 has a plurality of elongated blades (blades) arranged on the circumference, accommodates a fan 1 that is cylindrical as a whole, and the fan 1, and has an air passage inside. And a bell mouth 3 attached to both side surfaces of the scroll casing 2 on an extension line of the rotation center of the fan 1 (hereinafter simply referred to as a rotation axis). The fan 1 has a rotation center, and sucks air by rotating and blows out the air. The scroll casing 2 includes a suction opening 2a formed on the rotation shaft, a blowout opening 2b for blowing air taken in from the suction opening 2a toward the target area, and a scroll casing shape in the rotation circumferential direction of the fan 1. An air path 2c that is formed in a (curved shape) and communicates the suction port 2a and the air outlet 2b.

  The bell mouth 3 is formed with an opening and is attached to the suction port 2a of the scroll casing 2 so that the air taken in from the suction port 2a can be collectively accelerated and supplied to the fan 1. The fan 1 may be configured so that the fan diameter D is, for example, φ192 mm, the width L is, for example, 150 to 400 mm, and the number of blades is, for example, 40 sheets. The scroll casing 2 may be configured with a scroll casing height H of 246 mm. The shape of the bell mouth 3 is not particularly limited, and may be determined according to the length of the fan diameter D, for example.

FIG. 4 is a graph showing the PQ characteristic and Ks-Q characteristic of the sirocco fan 100. Based on FIG. 4, the PQ characteristic and the Ks-Q characteristic of the sirocco fan 100 will be described. Here, P represents static pressure [Pa], Q represents air volume [m ³ / min], and Ks represents specific noise [dB]. The specific noise Ks is calculated based on the equation Ks = SPL-10 · log ₁₀ (P · Q ^2.5 ). Note that SPL represents a noise level, and is generated from the sirocco fan 100 at a position about 1 m along the rotation axis from the center of the bell mouth 3 attached to the suction port 2a of the scroll casing 2. The measured value of noise is used. Also, black circles indicate PQ characteristics and white circles indicate Ks-Q characteristics. Furthermore, (1) to (3) indicate operating points.

  The PQ characteristic indicates the relationship between the static pressure P (left vertical axis), which is the ventilation resistance, and the air volume Q (horizontal axis) in a state where the rotation speed of the fan 1 is constant. As represented by the black circles in FIG. 4, the smaller the static pressure, the easier the wind flows in the air path 2c, and the greater the static pressure, the less likely the wind flows in the air path 2c. That is, it is easy to obtain the air volume at the operating point (3), and it is difficult to obtain the air volume at the operating point (1). Therefore, the air volume increases as the static pressure decreases, and the air volume decreases as the static pressure increases. In the following description, the high static pressure and low air volume side is referred to as the cutoff side (upper left side of the graph), and the low static pressure and high air volume side is referred to as the open side (lower right side of the graph).

  However, as shown in FIG. 4, even if the air volume is reduced, a region where the static pressure is reduced locally exists. This region is called a surging region (enclosed by a broken line in FIG. 4). In such a surging region, the air flow in the air passage 2c tends to become unstable. In other words, the surging region is a region that is likely to cause abnormal noise due to unstable air flow. Note that the specific noise Ks (right vertical axis) increases as the air volume Q increases, as indicated by the white circles in FIG. The specific noise Ks is a noise value considering the static pressure P and the air volume Q.

FIG. 5 is a graph showing the relationship between L ₀ / H ₀ of the sirocco fan 100 and the loss coefficient ξ. Based on FIG. 5, the relationship between L ₀ / H ₀ of the sirocco fan 100 and the loss coefficient ξ ₀ will be described. In FIG. 5, the scroll casing height H ₀ is fixed to 246 mm, the fan width dimension L ₀ is changed to 150 to 500 mm, and the loss coefficient ξ ₀ = P ₀ / Q ₀ ² [Pa / (m ³ / min) ² ] represents the relationship between L ₀ / H ₀ and the loss coefficient ξ ₀ using the width dimension L _{0 at} which the specific noise Ks is minimized. In FIG. 5, the vertical axis represents L ₀ / H ₀ and the horizontal axis represents the loss coefficient ξ ₀ .

The loss coefficient ξ ₀ = P ₀ / Q ₀ ² indicates that on the PQ characteristic shown in FIG. 4, the larger the loss coefficient ξ ₀ is, the closer to the closing side, and the smaller the loss coefficient ξ ₀ is, the closer to the open side. Yes. Note that the loss coefficient is a value determined by the position of an operating point (P, Q) described later. L ₀ / H ₀ represents a ratio when the scroll casing height H ₀ is fixed and the width dimension L ₀ is changed. From FIG. 5, it can be seen that the width dimension L _{0 at} which the specific noise Ks is minimized is changed by the loss coefficient ξ ₀ . That is, the smaller opening side is the loss coefficient xi] _0, the width dimension L ₀ where the specific noise Ks becomes minimum is the longer. Therefore, from FIG. 5, when the loss coefficient ξ is in the range of 0.1 ≦ ξ ≦ 0.4, f (ξ ₀ ) = 0.34947ξ ₀ ² −1.0554ξ ₀ +1.8 and L ₀ / When H ₀ = f (ξ ₀ ), the specific noise Ks is minimized. Note that f (ξ ₀ ) = 0.349494ξ ₀ ² −1.0554ξ ₀ +1.8 is an equation calculated from the graph shown in FIG.

Next, the reason why the specific noise Ks changes depending on the loss coefficient ξ ₀ and the width dimension L ₀ will be described.
FIG. 6 is a graph showing the PQ characteristic and the Ks-Q characteristic of the sirocco fan 100 when the width dimension L ₀ is 230 or 300 mm and the operating point A is passed. The black circle indicates the PQ characteristics when the width L is 230 mm, the white circle indicates the PQ characteristics when the width L ₀ is 300 mm, and the black triangle indicates The Ks-Q characteristics when the width dimension L ₀ is 230 mm and the Ks-Q characteristics when the white triangle mark the width dimension L ₀ is 300 mm are shown. The operating point described here is determined by the design air volume of the unit and the design static pressure (the ventilation resistance of the heat exchanger, the ventilation path of the unit, the duct, the ventilation resistance of the filter, etc.). The

When the PQ characteristics passing through the operating point A are compared when the width dimension L ₀ is 230 mm and 300 mm, the 300 mm longer width dimension L ₀ has a surging region at the lower right (PQ characteristics graph). It can be seen that the movement point is close to the operating point A. From the PQ characteristic and the Ks-Q characteristic shown in FIG. 6, it can be seen that the operating point at which the specific noise Ks is minimum is in the vicinity of the surging region. However, if the operating point is in or near the surging region, the flow becomes unstable, reverse suction or abnormal noise occurs, and the air flow time fluctuation increases. Therefore, in order to reliably form a stable flow, the operating point needs to be on the open side with respect to the surging region.

  That is, when the volume of the fan is increased with respect to a certain operating point (P, Q), the surging area moves to the lower right in the PQ characteristic diagram. At this time, as the operating point is further away from the surging region to the open side (that is, the lower right side of the PQ characteristic diagram), the more abnormal sound is generated. This is because the static pressure fluctuation increases in a region where the distance between the tongue of the casing (2b1 shown in FIG. 3) and the bell mouth fan is short. In the present invention, the volume of the fan is increased with respect to a predetermined operating point, and the surging area is moved to bring the operating point and the surging area as close as possible to reduce the generated noise. .

  Here, in order to increase the volume of the fan, it is conceivable to increase the fan diameter or increase the fan width. However, increasing the fan diameter unnecessarily increases the unit height. In the present invention, the fan width is made larger than before without unnecessarily increasing the unit height, and the relationship between the operating point and the surging area can be optimized, so that there are few unit installation restrictions and noise is reduced. A unit that can be obtained.

FIG. 7 is a graph showing the relationship between the airflow between the blades for each blade of the fan 1 and the position of the blade. Based on FIG. 7, the relationship between the airflow between the blades and the position of the blades of each blade of the fan 1 constituting the sirocco fan 100 will be described. In FIG. 7, the vertical axis represents the inter-blade air volume (m ³ / min) for each blade, and the horizontal axis represents the position of the blade. In FIG. 7, the black circles indicate the relationship between the blade air volume for each blade at the operating point (1) and the position of the blades, and the white diamonds indicate the blade 1 at the operating point (2). The relationship between the airflow between the blades and the position of the blades for each sheet, and the black triangle indicates the relationship between the airflow between the blades and the position of the blades at the operating point (3). .

  In FIG. 7, the inter-blade air volume for each blade of the fan 1 shown on the vertical axis is positive when the wind is flowing from the inner periphery to the outer periphery of the blade (blade), and the wind is The case of the flow from the outer peripheral side to the inner peripheral side is shown as negative. Further, in FIG. 7, the position of the blade shown on the horizontal axis is represented by a short hand of a watch. That is, the position of the blade is replaced with the position of the short hand of the watch from 00:00 to 12:00. Furthermore, the operating points (1) to (3) shown in FIG. 7 indicate the same operating points as the operating points (1) to (3) shown in FIG.

As shown in FIG. 7, it can be seen that the airflow between the blades is larger on the open side and smaller on the shut-off side when the position of the blade is in the vicinity of 10:30. Further, it can be seen that there is no significant difference in the airflow between the blades in the region other than 9:30 to 11:30. Assuming that the airflow between the blades is Qi (i = 1 to 40 when the number of blades is 40), the following formulas (Equation (1) and Equation (1) 2)) is established.
Formula (1) SPL∝Σ10 · log ₁₀ Qi ⁶
Formula (2) W∝ΣQi ³

Therefore, the noise value SPL and the fan input value W become smaller as the distribution of the inter-blade air volume Qi is more uniform. That is, as shown in FIG. 4, in the case of the operating point (1) close to the surging region, since the distribution of the inter-blade air volume Qi is uniform, the specific noise Ks is minimized. Here, as described above, on the contrary, the closer the operating point is to the surging region, that is, the closer to L ₀ / H ₀ = f (ξ ₀ ), the smaller the specific noise Ks, but L ₀ / H ₀ = f. If (ξ ₀ ) is exceeded, the operating point is included in the surging region, and the specific noise Ks is worsened. On the other hand, the further away the operating point is on the open side than the surging region, the more static pressure fluctuations occur in the region where the distance between the casing tongue (2b1 shown in FIG. 3) and the bell mouth fan is shorter. Abnormal noise is likely to occur due to the increase.

Therefore, when 0 <n ≦ 1, L ₀ / H ₀ = n × f (ξ ₀ ), the loss factor is small (the air volume is large and the ventilation resistance is small), that is, 0.1 ≦ ξ ₀ ≦ 0. In the range of .4, n = 0.75 was obtained when the minimum n at which no abnormal sound was generated was obtained. Therefore, when the loss factor is small (the air volume is large and the ventilation resistance is small), that is, in the range of 0.1 ≦ ξ ₀ ≦ 0.4, 0.75f (ξ ₀ ) ≦ L ₀ / H ₀ ≦ f If (ξ ₀ ), the specific noise Ks is small, and it is possible to form a flow in which no abnormal noise occurs.

In the above description, the case where the casing height H ₀ = 246 mm has been described, but the case where the dimensions of the casing height are generalized will be described. Let k be a constant, and H = kH ₀ , L = kL ₀ , and D = kD ₀ . When the dimensions change, the following equations (Equation (3) and Equation (4)) are established for P and Q from the similarity law. Here, N is the rotational speed.
Formula (3) P = P ₀ (D / D ₀ ) ² (N / N ₀ ) ²
Formula (4) Q = Q ₀ (D / D ₀ ) ³ (N / N ₀ )

When N / N ₀ is deleted and rearranged from the equations (3) and (4), the equation (5) is established.
Formula (5) P ₀ / Q ₀ ² = P / Q ² (D / D ₀ ) ⁴
By substituting ξ = P / Q ² and D = kD ₀ into equation (5), equation (6) is established.
Formula (6) ξ ₀ = k ⁴ ξ
Using equation (6) and H = kH ₀ , L = kL ₀ ,
0.1 ≦ ξ ₀ ≦ 0.4 is 0.1 ≦ k ⁴ ξ ≦ 0.4
0.75 f (ξ ₀ ) ≦ L ₀ / H ₀ ≦ f (ξ ₀ ) can be generalized as 0.75 f (k ⁴ ξ) ≦ L / H ≦ f (k ⁴ ξ).

  That is, when the fan 1 is used in an air conditioner in which a heat exchanger is provided on the downstream side of the fan, when the loss factor is small (the air volume is large and the ventilation resistance is small), the fan width is increased. Since the noise is low and the speed distribution in the width direction of the heat exchanger approaches uniformly, it is not necessary to unnecessarily increase the power consumption of the compressor.

Next, the case where the sirocco fan 100 is a single suction type will be described.
The above-described L may be replaced with L / 2, and Q may be replaced with Q / 2. If g (ξ) = f {P / (Q / 2) ² }, then g (k ⁴ ξ) = 1.39788 (k ⁴ ξ) ² -2.1108 (k ⁴ ξ) +1.8. 1.5 g (k ⁴ ξ) ≦ L / H ≦ 2 g (k ⁴ ξ). That is, in the case where the sirocco fan 100 is a single suction type, 1.5 g (k ⁴ ξ) ≦ L / H ≦ 2 g (k ⁴ ξ) in the range of 0.1 ≦ k ⁴ ξ ≦ 0.4. This means that a unit having a small specific noise Ks and no abnormal noise can be formed.

In the above description, the case of the sirocco fan 100 alone has been described. However, the operating point when the sirocco fan 100 is mounted on a unit such as an air conditioner, a dehumidifier, or an air purifier can be similarly determined. . In such a case, the rotational speed N _{1 of} the unit and the air volume Q ₁ of the unit are obtained, and the static pressure P ₁ is calculated using the rotational speed N ₁ and the air volume Q ₁ from the PQ characteristics of the sirocco fan 100 alone. You just have to ask for it. When m fans are mounted on the unit, the loss coefficient may be obtained by setting the air volume of one fan as Q ₁ / m and the static pressure as P ₁ .

As is clear from the above description, when the sirocco fan 100 is of the double suction type, 0.75 f (k ⁴ ξ) ≦ L / H ≦ f (k in the range of 0.1 ≦ k ⁴ ξ ≦ 0.4. with ⁴ xi]), can be specific noise Ks is small, to form a stable flow. Further, when the sirocco fan 100 is a single suction type, 1.5 g (k ⁴ ξ) ≦ L / H ≦ 2 g (k ⁴ ξ) is set in the range of 0.1 ≦ k ⁴ ξ ≦ 0.4. The specific noise Ks is small and a stable flow can be formed.

  FIG. 8 is a schematic cross-sectional view showing a vertical cross-sectional configuration of the bell mouth 3. FIG. 9 is a perspective view of the sirocco fan 100 showing the region α of the bell mouth 3. FIG. 10 is an enlarged view of the region α showing the rms value of the static pressure fluctuation on the wall surface of the region α having no step. FIG. 11 is an enlarged view of the region α showing the rms value of the static pressure fluctuation on the wall surface of the region α having a step. Based on FIGS. 8 to 11, the bell mouth 3 attached to the sirocco fan 100 is characterized in that the bell mouth 3 is attached to form a step on the side surface of the scroll casing 2 and the step is formed on the side surface of the scroll casing 2. A description will be given while comparing it with the one to which the bell mouth 3 is attached.

  In the longitudinal cross-sectional configuration of the bell mouth 3 shown in FIG. 8, end points on the sirocco fan 100 side (end points at the minimum opening of the bell mouth 3) are point A and point A ′ (point A and point with respect to the center of the bell mouth 3). The other end point (the end point at the maximum opening of the bellmouth 3) is the point B and the point B ′ (the point that is point-symmetric with the point B with respect to the center of the bellmouth 3), the point B The point of intersection between the straight line drawn in the direction of the fan 1 and the side of the scroll casing 2 is point C, the point of intersection of the straight line drawn from the point B ′ in the direction of the fan 1 and the side of the scroll casing 2 is point C ′, and the line segment AA ′. The point O is the intersection of the fan 1 and the rotation axis extension line of the fan 1.

  That is, when BC> 0, the bell mouth 3 is attached so that a step is formed on the side surface of the scroll casing 2, and when BC = 0, the bell mouth 3 is attached so that no step is formed on the side surface of the scroll casing 2. . In addition, when BC> 0, the length of BC is 5 [mm], and the rms value of static pressure fluctuations other than the region α is approximately 0 [Pa]. 9 to 11, depending on how the bell mouth 3 is attached as shown in FIG. 8, the static pressure fluctuation in the case where the step is formed on the side surface of the scroll casing 2 and the static pressure fluctuation in the case where the step is not formed. Are shown in comparison.

The definition formula of the rms value of the static pressure fluctuation is shown below.
Expression (7) p _s (t) = p _s + p _s ′ = (t)
Formula (8) rms value = {(Σp _s ' (t) ² ) / N} ^0.5
Here, p _s represents a time average value, and p _s ′ (t) represents a fluctuation value of the static pressure.
The greater the rms value of the static pressure fluctuation on the wall surface, the greater the noise generated from the wall surface. 10 and 11, it can be seen that the static pressure fluctuation in the case where the step is formed on the side surface of the scroll casing 2 is smaller than the static pressure fluctuation in the case where the step is not formed. Therefore, the generated noise can be reduced by forming a step on the side surface of the scroll casing 2.

  FIG. 12 is a longitudinal sectional view showing a schematic sectional configuration of the sirocco fan 100. FIG. 13 is a perspective view of the sirocco fan 100 seen through. A region where the rms value of the static pressure fluctuation in the sirocco fan 100 is large will be described with reference to FIGS. Further, in FIG. 12, a curved portion from the air passage 2 c of the scroll casing 2 constituting the sirocco fan 100 to the air outlet 2 b and a portion closest to the outer peripheral portion of the fan 1 is illustrated as a tongue portion 4. Yes.

  In FIG. 13, the point at which the distance from the fan 1 is minimum on the intersection line between the plane passing through the points A, O and A ′ shown in FIG. The point closest to D is point E, the point located at point O in the counter-rotating direction 65 ° from point E is point F, the point F is centered on point O from point F to the counter-rotating direction 40 ° of fan 1 A point located at point G, a point located at a point 40 ° from the point F in the rotation direction of the fan 1 around the point O, a point H located at a point H from the point F, and a point located at the rotation direction 180 ° from the point F around the point O. Illustrated as point I.

  When the region is defined in this way, it has been found that the region where the rms value of the static pressure fluctuation in the sirocco fan 100 is large is a region of a substantially circular arc HFG connecting the points H, F, and G. Therefore, when the length of the line segment BC in the arc HFG is X and the length of the line segment BC in the substantially arc HIG (the arc connecting point H, point I, and point G) is Y, L / H ≦ f ( In the range of ξ) or L / H ≦ g (ξ), if the bell mouth 3 satisfies X> Y ≧ 0, the rms value of the static pressure fluctuation can be reduced and the noise can be reduced.

  As shown in FIGS. 10 and 11, when no step is formed on the side surface of the scroll casing 2, the rms value of the static pressure fluctuation in the region of the arc HFG is 7 Pa at maximum, but the step is formed on the side surface of the scroll casing 2. When formed, the rms value of the static pressure fluctuation in the arc HFG region is 1 Pa or less at maximum. That is, by forming a step on the side surface of the scroll casing 2, noise using the bell mouth 3 as a sound source is reduced. The reason for this is considered to be that the distance from the fan 1 is increased by the amount of the step, that is, the length of the line segment BC, and the static pressure fluctuation caused by the rotation of the fan 1 is suppressed. Because.

FIG. 14 is a graph showing the PQ characteristic of the sirocco fan 100 when passing through the operating point B. FIG. Based on FIG. 14, the PQ characteristic when passing through the operating point B of the sirocco fan 100 in which a step is formed on the side surface of the scroll casing 2, and the operation of the sirocco fan 100 in which no step is formed on the side surface of the scroll casing 2. PQ characteristics when passing through point B will be described. In FIG. 14, black circles indicate the PQ characteristics of the sirocco fan 100 in which no step is formed on the side surface of the scroll casing 2, and white circles indicate that the sirocco fan 100 has a step in the side surface of the scroll casing 2. PQ characteristics are shown respectively. In FIG. 14, the vertical axis represents the static pressure P [Pa], and the horizontal axis represents the air volume Q [m ³ / min].

  As shown in FIG. 14, when the surging area is compared between the sirocco fan 100 in which the step is formed on the side surface of the scroll casing 2 and the sirocco fan 100 in which the step is not formed on the side surface of the scroll casing 2, the former is opened. You can see that it is on the side. When the sirocco fan 100 in which a step is formed on the side surface of the scroll casing 2 is mounted on a unit such as an air conditioner, a dehumidifier, or an air purifier, the width dimension of the sirocco fan 100 may be increased due to unit dimensional constraints. There are things that cannot be done. In other words, since the width dimension is short, when the operating point is on the open side of the surging area where the specific noise is minimized, the surging area can be brought closer to the operating point, which is effective for reducing noise. .

  FIG. 15 is a plan view showing a schematic overall configuration of the ceiling-suspended indoor unit 110 on which the sirocco fan 100 is mounted. FIG. 16 is a cross-sectional view illustrating a vertical cross-sectional configuration of the ceiling-suspended indoor unit 110. Based on FIG.15 and FIG.16, the static pressure fluctuation | variation at the time of mounting the sirocco fan 100 which formed the level | step difference in the side surface of the scroll casing 2 in the ceiling-suspended indoor unit 110 is demonstrated. FIG. 15 illustrates a case where two sirocco fans 100 are mounted and the suction space 5 is formed on each side surface in the width direction. In FIG. 16, the air flow is indicated by arrows.

  When the sirocco fan 100 in which a step is formed on the side surface of the scroll casing 2 is mounted on the ceiling-suspended indoor unit 110, the suction space 5 may be reduced by the amount of the step, which may increase noise. is there. From the above description, the region where the rms value of the static pressure fluctuation is large is the arc HFG, and the rms value of the static pressure fluctuation is less affected by the distance from the fan 1 in the other regions. Therefore, if the sirocco fan 100 in which a step is formed in the region of the arc HFG is mounted on the ceiling-suspended indoor unit 110, the step can be positioned on the downstream side of the suction port 2a, and the reduction of the suction space 5 can be reduced. .

FIG. 17 is a table showing noise values in the ceiling-suspended indoor unit 110. Based on FIG. 17, the noise value generated from the ceiling-mounted indoor unit 110 on which the sirocco fan 100 having a step formed on the side surface of the scroll casing 2 is mounted, and the sirocco fan 100 having no step formed on the side surface of the scroll casing 2 is mounted. The noise value generated from the ceiling-suspended indoor unit 110 will be described. It is assumed that the step is formed in the area of the arc HFG. Also, the blowing air volume is 16m ³ The noise value when / min is shown.

As shown in FIG. 17, when the air flow rate is 16 m ³ / min, the noise value in the step formed in the arc HFG region is 42.4 [dB], and the step is formed in the arc HFG region. It was found that the noise value in the case of not performing was 44.0 [dB]. Thus, the noise value can be reduced by forming a step in the region of the arc HFG. As described above, by providing a step in the region of the arc HFG, it is possible to suppress the reduction of the suction space 5 and reduce the noise value.

Embodiment 2.
FIG. 18 is a schematic configuration diagram illustrating a schematic configuration of the air-conditioning apparatus 150 according to Embodiment 2 of the present invention. Based on FIG. 18, the structure of the air conditioning apparatus 150 is demonstrated. This air conditioner 150 is mounted with the sirocco fan 100 according to the first embodiment. This sirocco fan 100 is assumed to be mounted on an indoor unit (indoor unit) constituting the air conditioner 150 in the vicinity of the heat exchanger. In the second embodiment, the differences from the first embodiment will be mainly described, and the same parts as those in the first embodiment are denoted by the same reference numerals and the description thereof will be omitted.

  The air conditioner 150 is configured by sequentially connecting a compressor 151, a condensing heat exchanger 152, an expansion device 153, and an evaporating heat exchanger 154 with refrigerant piping. Among these, the sirocco fan 100 which concerns on Embodiment 1 shall be provided in the indoor unit in which the condensation heat exchanger 152 or the evaporative heat exchanger 154 is installed. That is, the sirocco fan 100 is provided in the vicinity of the condensing heat exchanger 152 or the evaporating heat exchanger 154 installed in the indoor unit, and has a function of supplying air to the condensing heat exchanger 152 or the evaporating heat exchanger 154. is doing.

  The compressor 151 sucks the refrigerant flowing through the refrigerant pipe and compresses the refrigerant to a high temperature / high pressure state. The condensation heat exchanger 152 exchanges heat between air and the refrigerant, and condenses and liquefies the refrigerant. The expansion device 153 expands the refrigerant by reducing the pressure. The evaporative heat exchanger 154 exchanges heat between air and the refrigerant, and evaporates and gasifies the refrigerant. The noise transmitted to the room by mounting the sirocco fan 100 according to the first embodiment on the indoor unit in which the condensation heat exchanger 152 or the evaporation heat exchanger 154 constituting the air conditioner 150 is installed. Can be reduced.

  Here, operation | movement of the air conditioning apparatus 150 is demonstrated easily. The arrows shown in FIG. 18 indicate the flow direction of the refrigerant. The refrigerant gas that has been compressed by the compressor 151 and has become high temperature and high pressure flows into the condensation heat exchanger 152. In the condensing heat exchanger 152, the refrigerant is condensed by exchanging heat with air to become a low-temperature / high-pressure liquid refrigerant or a gas-liquid two-phase refrigerant. The refrigerant that has flowed out of the condensing heat exchanger 152 is then decompressed by the expansion device 153 and flows into the evaporating heat exchanger 154 as a low-temperature / low-pressure liquid refrigerant or a gas-liquid two-phase refrigerant. In the evaporative heat exchanger 154, the refrigerant evaporates by exchanging heat with air, becomes high-temperature / low-pressure refrigerant gas, and is sucked into the compressor 151 again. During the heating operation, the condensation heat exchanger 152 is mounted on the indoor unit, and during the cooling operation, the evaporative heat exchanger 154 is mounted on the indoor unit.

  When the loss factor is small and the fan width is long, the speed distribution in the width direction of the heat exchanger approaches uniformly, and the heat transfer area of the heat exchanger is more effective than when the fan width is short and the speed distribution is not uniform. Can be used for For this reason, the temperature difference between the air and the refrigerant necessary to obtain a predetermined air conditioning capacity is reduced, the compressor input is reduced, and the noise is reduced. If the loss coefficient is small, noise can be reduced by increasing the fan width without increasing the fan diameter. Further, in an air conditioner having a plurality of fans having a short fan width, the noise value of the air conditioner at a predetermined operating point can be reduced even if the number of fans is reduced by replacing with a fan having a longer fan width. In addition, the speed distribution in the width direction of the heat exchanger can be made to be uniform.

Claims (5)

An inlet for taking in air, an outlet for blowing out air, and a scroll casing having an air passage from the inlet to the outlet;
A fan that is housed in the scroll casing and rotationally driven to take in air from the inlet and blow out air from the outlet;
A bell mouth attached to the suction port of the scroll casing,
The suction port is on an extension line of the rotation center of the fan and formed on both side surfaces of the scroll casing.
The ventilation resistance in the air passage is P [Pa], the amount of air taken in from the suction port is Q [m ³ / min], the width in the rotation axis direction of the fan is L [mm], and k is a constant, When the height of the scroll casing is H = 246 k [mm] and P / Q ² is the loss factor ξ [Pa / (m ³ / min) ² ],
In the range of 0.1 ≦ k ⁴ ξ ≦ 0.4,
^{f (k 4 ξ) = 0.34947} (k 4 ξ) and ^{2 -1.0554 (k 4 ξ) +1.8} , and ^{0.75f (k 4 ξ) ≦ L} / H ≦ f (k 4 ξ) A sirocco fan characterized by In the curved portion from the air passage of the scroll casing to the outlet, the portion closest to the outer periphery of the fan is a tongue,
In the longitudinal section of the bellmouth,
The end point at the minimum opening of the bell mouth is point A,
A point A ′ which is symmetric with respect to the point A with respect to the center of the bell mouth,
The end point at the maximum opening of the bell mouth is point B,
A point B ′ which is symmetric with respect to the point B with respect to the center of the bell mouth,
An intersection of a straight line drawn from the point B in the direction of the fan and the side surface of the scroll casing is a point C,
An intersection of a straight line drawn from the point B ′ in the direction of the fan and the side surface of the scroll casing is a point C ′,
The point of intersection of the line segment AA ′ and the rotation axis extension line of the fan is point O,
On the intersection line between the plane passing through the point A, the point O and the point A ′ and the tongue, the point where the distance from the fan is minimum is the point D,
Point E closest to point D of the bell mouth
A point located at 65 ° in the counter-rotating direction of the fan from the point E around the point O is a point F,
A point located at 40 ° in the counter-rotating direction of the fan from the point F with the point O as the center is a point G,
A point located in the rotational direction of the fan 40 ° from the point F with the point O as the center, a point H, a point located in the rotational direction 180 ° from the point F around the point O, the point I,
The length of a line segment BC in a substantially arc HFG connecting the point H, the point F, and the point G is X,
When the length of the line segment BC in the substantially arc HIG connecting the point H, the point I and the point G is Y,
In the range of L / H ≦ f (k ⁴ ξ),
The sirocco fan according to claim 1, wherein X> Y ≧ 0. An inlet for taking in air, an outlet for blowing out air, and a scroll casing having an air passage from the inlet to the outlet;
A fan that is housed in the scroll casing and rotationally driven to take in air from the inlet and blow out air from the outlet;
A bell mouth attached to the suction port of the scroll casing,
The suction port is on an extension line of the rotation center of the fan, and is formed on one side surface of the scroll casing.
The ventilation resistance in the air passage is P [Pa], the amount of air taken in from the suction port is Q [m ³ / min], the width in the rotation axis direction of the fan is L [mm], and k is a constant, When the height of the scroll casing is H = 246 k [mm] and P / Q ² is the loss factor ξ [Pa / (m ³ / min) ² ],
In the range of 0.1 ≦ k ⁴ ξ ≦ 0.4,
g (k ⁴ ξ) = 1.39788 (k ⁴ ξ) ² -2.1108 (k ⁴ ξ) +1.8, and 1.5 g (k ⁴ ξ) ≦ L / H ≦ 2 g (k ⁴ ξ) A sirocco fan characterized by In the curved portion from the air passage of the scroll casing to the outlet, the portion closest to the outer periphery of the fan is a tongue,
In the longitudinal section of the bellmouth,
The end point at the minimum opening of the bell mouth is point A,
A point A ′ which is symmetric with respect to the point A with respect to the center of the bell mouth,
The end point at the maximum opening of the bell mouth is point B,
A point B ′ which is symmetric with respect to the point B with respect to the center of the bell mouth,
An intersection of a straight line drawn from the point B in the direction of the fan and the side surface of the scroll casing is a point C,
An intersection of a straight line drawn from the point B ′ in the direction of the fan and the side surface of the scroll casing is a point C ′,
The point of intersection of the line segment AA ′ and the rotation axis extension line of the fan is point O,
On the intersection line between the plane passing through the point A, the point O and the point A ′ and the tongue, the point where the distance from the fan is minimum is the point D,
Point E closest to point D of the bell mouth
A point located at 65 ° in the counter-rotating direction of the fan from the point E around the point O is a point F,
A point located at 40 ° in the counter-rotating direction of the fan from the point F with the point O as the center is a point G,
A point located in the rotational direction of the fan 40 ° from the point F with the point O as the center, a point H, a point located in the rotational direction 180 ° from the point F around the point O, the point I,
The length of a line segment BC in a substantially arc HFG connecting the point H, the point F, and the point G is X,
When the length of the line segment BC in the substantially arc HIG connecting the point H, the point I and the point G is Y,
In the range of L / H ≦ g (k ⁴ ξ),
The sirocco fan according to claim 3, wherein X> Y ≧ 0. An air conditioner using the sirocco fan according to any one of claims 1 to 4.

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