Guided air device, ventilation device with a guided air device and methods for increasing the efficiency and / or performance of ventilation devices

Abstract

A guide vane (1) for extending a fan (2) is proposed. According to the invention, the guide vane (1) has several guide elements (4) for influencing the airflow leaving the fan (2). Furthermore, a ventilation device (6) comprising a turbomachine with such a fan (2) and a diffuser is proposed. In addition, a method for increasing the efficiency and / or performance of ventilation devices in air handling systems is proposed, wherein a guide vane (1) influences the airflow downstream of a fan (2) in the direction of airflow, in particular radially outwards as a radial extension.

Description

[0001] The present invention relates to a guide device, a ventilation device with a guide device and a method for increasing the efficiency and / or performance of ventilation devices, in particular for air-conditioning systems.

[0002] From DE 384 0 268 C1 an air blow-out device is known which arranges a diffuser in the outlet plane of a blow-out vortex chamber.

[0003] A fan with a diffuser is known from EP 2 815 130 B1, the object here being to design a generic diffuser, a generic fan and a device in such a way that the space on the devices can be optimally used without the need for a complex design. In the diffuser according to EP 2 815 130 B1, the transitions between the sides of the wall have a twist in the vertical direction that follows the swirl of the air flow through the diffuser. The transitions therefore do not run in a straight line in the vertical direction of the diffuser wall, but are curved accordingly. The transition areas are designed to follow the direction of air flow in the diffuser or the swirl of the flow behind the fan impeller. This results in only minimal losses in the area of ​​these transitions.

[0004] Even advantageously used free-running radial fans still offer potential for efficiency improvements. Energy losses occur as a result of the actual efficiencies of all installed components. The system efficiency of the fan unit η S is formed from the product of the individual efficiencies of the installed components. These are the efficiency of the control device η R (e.g. frequency converter), the efficiency of the motor used η M and the efficiency of the fan η V (Eq. 1.1).

[0005] Furthermore, the system efficiency is defined as the ratio between the air flow P L and the electrical power P absorbed from the power grid el .(Eq. 1.2). The air performance is in turn formed from the product of the air volume flow V delivered by the fan impeller and the static pressure increase between the suction and pressure sides of the fan impeller Δp stat(Eq. 1.3). ηS=ηR⋅ηM⋅ηV ηS=PLPel PL=V˙⋅Δpstat

[0006] This object is achieved by a guide device, a ventilation device with a guide device, a method for increasing the efficiency and / or performance of ventilation devices and / or one of the uses according to one of the independent claims.

[0007] Advantageous embodiments are specified in subclaims and described below and shown in figures.

[0008] To increase efficiency, it is proposed to extend a fan by a guide device, in particular to extend a free-running radial fan by a guide device, which increases the efficiency of the fan unit, among other things, through a diffuser effect.

[0009] In addition, a method for increasing the efficiency or for operating a ventilation device is proposed, wherein a guide device following a fan in the air flow direction, in particular radially outward as a radial extension, influences the air flow, in particular bringing about a swirl reduction.

[0010] The efficiency increase is preferably achieved in two ways. First, the fan impeller is extended, for example, with a plate diffuser. Second, the swirl of the air flowing out of the fan impeller is reduced by the deflection device.

[0011] The plate diffuser is preferably implemented as two circular rings, one mounted in front of and one behind the fan impeller. The plate diffuser can create the effect of an enlarged outlet area of ​​the fan impeller. This results in part of the dynamic pressure generated by the fan being converted into static pressure, thereby increasing efficiency.

[0012] In general, a distinction is made between the dynamic pressure p d , the static pressure p stat and the altitude energy p hThe dynamic pressure also depends on the air density ρ and the average flow velocity c of the air stream (Eq. 1.4). The static pressure is the pressure that can be measured perpendicular to a flow. The altitude energy is composed of the air density ρ, the geodetic height h, and the acceleration due to gravity g (Eq. 1.5). The three quantities can be linked using the Bernoulli equation (Eq. 1.6). Since the geodetic height on the test bench used can be set to zero meters, the altitude energy could be neglected, which simplifies the equation (Eq. 1.7). pd=ρ2⋅c2 ph=ρ⋅h⋅g ρ2⋅c2+pstat+ρ⋅h⋅g=constant ρ2⋅c2+pstat=constant

[0013] If the solution developed here succeeds in reducing the proportion of dynamic pressure behind the fan impeller, more usable static pressure can be generated according to Equation 1.7. The static pressure increase of the fan could be increased. From Equation 1.4 it can be seen that the level of dynamic pressure depends essentially on the flow velocity. It is specifically proposed to decelerate the airflow behind the fan impeller. This increased the proportion of static pressure (Equation 1.7). According to the continuity equation (Equation 1.8), it is theoretically sufficient to increase the cross-section A through which the air flows in order to reduce the flow velocity. In practice, however, the design of the cross-section expansion is not easily feasible.

[0014] By means of the objects proposed in the independent claims, a not too abrupt enlargement is achieved.

[0015] Secondly, in the advantageous embodiments proposed here, a reduction in the swirl of the air flowing out of the fan impeller is achieved by supplementing a diffuser with guide vanes, in particular in the form of a bladed plate diffuser.

[0016] The invention is described in more detail below with reference to the figures. Fig. 1a a guide device according to a first embodiment, Fig. 1b a guide device according to a second embodiment, Fig. 1c a ventilation device with a guide vane mounted radially around a fan impeller, Fig. 2 a guide element of the guide device made of Fig. 1a in separate perspective view, Fig. 3 the guide device Fig. 1a in a schematic axial side view looking at the short side of the guide elements according to Fig. 2 and Fig. 4 a representation to illustrate an embodiment of an advantageous method with three positions of the adjustable in the guide device according to Fig. 1a arranged guide elements according to Fig. 2.

[0017] The Fig. 1 to 4 show at least details and also a possible installation situation of a guide vane 1 for extending a fan 2 with a fan housing 3, in the illustrated embodiment a radial fan. The guide vane 1 has several guide elements 4 for influencing the air flow leaving the fan 2. In Fig. 4 air currents are marked with arrows.

[0018] An aerodynamic profile is preferably used as the guide element 4. The basic structure of the ventilation device 6 with the guide device 1 can Fig. 1 and Fig. 2. The plate diffuser, shown here as an example of an advantageous guide device but not limiting the invention to this embodiment, is preferably implemented by two circular rings 40, one of which is mounted in front of and one behind the fan impeller. The plate diffuser can achieve the above-described effect of an enlarged outlet area of ​​the fan impeller.

[0019] The efficiency changes of the guide vane system on the flow process of the fan unit were measured in terms of the air flow and the electrical power consumption of the fan unit. The system efficiency calculated from these values ​​serves as the primary parameter for evaluating the proposed guide vane system variants.

[0020] The number of guide vanes depends on the fan's operating point within the performance map. The lower the flow rate, the higher the number of blades required. For the desired flow rate range, a number of 8 to 16 blades has proven optimal.

[0021] In addition to the effect of the blade geometry, the design of the rotated 3D diffuser was investigated to determine the effect on the system efficiency of the fan unit when the air flowing from the fan impeller is deflected into the flow direction of the system using the guide elements 4 of the guide device.

[0022] For this purpose, the guide element 4 was preferably rotated by 15°. The rotation took place around the tip of the guide vane facing the fan impeller ( Fig. 3). Furthermore, the side of the guide vane facing the bulkhead was lengthened by 38 mm 42. In the present test example, this corresponds to the maximum possible value by which the vane can be changed in its 42. The side facing the engine was shortened by 20 mm ( Fig. 3). The geometric changes resulted in the cover plate of the deflector facing the bulkhead having an outer diameter approximately 42.5 mm larger than the side facing the motor. This provides more space for the air flowing from the fan impeller to exit the deflector.

[0023] All dimensions are relative to the impeller diameter and refer to an impeller outer diameter of 455 mm.

[0024] The back of the blade is preferably rotated by 15°, cf. Fig. 3.

[0025] Numerous experiments have shown that at a constant speed, the airflow exits the fan impeller more radially as the volume flow increases. As the volume flow decreases, however, the airflow exits more tangentially. The exact exit angle also depends on the speed of the fan impeller and its blade geometry.

[0026] If the air flows "against" the guide elements 4, this leads to an increase in flow resistance and thus in flow losses. The air flow is slowed down and loses part of the energy transferred to it by the fan 2 without being converted into static pressure, which is reflected in a decrease in efficiency. If, on the other hand, the air flows along the guide vane, it can act as a guide vane and increase efficiency (see Fig. Fig. 4.

[0027] The guide elements 4 are preferably variable in their entire shape, for example, they can be cambered to a greater or lesser extent. Alternatively or additionally, they can be specifically modified with respect to the reference angles in the curvature angle 44 and / or the flank angle 45 and / or the tip angle 48 and / or the butt entry angle 49.

[0028] Depending on the operating point, it is further proposed to store a three-dimensional calculation model which specifies the optimal angle of attack of the guide elements 4.

[0029] For this purpose, the following parameters are continuously measured during operation of fan 2: 1. Volume flow 2. Speed

[0030] Based on these values, the optimal angle of attack of the guide elements 4 is set via at least one actuator.

[0031] As an extension of the optimization, it is proposed that a learning system independently determines the optimal operating point.

[0032] For example, the following parameters are continuously measured during operation of the fan: 1. Volume flow in m 3 / s 2. Static pressure increase in Pa 3. Electrical power consumption in watts 4. Speed ​​in 1 / min

[0033] Based on these values, the following parameters are preferably determined: 1. Air performance (product of volume flow and pressure increase) in watts 2. System efficiency (quotient of air output divided by electrical power consumption)

[0034] The diffuser's angle of attack is preset using an actuator based on a stored characteristic map (based on the volume flow and the engine speed). The actuator varies the angle of attack within a range from a minimum to a maximum possible angle of attack in order to seek optimum efficiency.

[0035] To do this, the angle of attack is first changed (e.g., decreased) in one direction, and the change in system efficiency is evaluated through continuous measurement. If the efficiency increases, the change is continued until a deterioration in efficiency occurs. The angle of attack with the highest efficiency is then approached and permanently set. The measurements and the corresponding angle of attack are stored in a database.

[0036] If the system efficiency decreases immediately, the value representing the highest efficiency is searched for in the other direction (e.g. increasing the angle of attack).

[0037] To improve convergence, a numerical optimization method, such as the line search method, is used. By varying the step size and search direction, the system's dynamics can be increased through faster adaptation cycles.

[0038] The optima found are stored in a database, on the basis of which a calculation model is built and constantly adapted so that the respective optimum can be quickly reached when operating conditions change.

[0039] An internal logic allows a variable cycle to be set in which periods an automatic check of the optima may be useful.

[0040] The same reference numerals used in the figures are often reused across the different embodiments to identify similar features, which is not intended to be inconsistent. This serves to facilitate comparability. List of reference symbols: 1 deflector 2 fans 3 fan housing 4 Guide element 5 axis 6 Ventilation device 40 circular ring 42 length 44 angles of curvature 45 flank angle 46 angle of attack 48 Pointed end angle 49 Blunt entry angle QUOTES CONTAINED IN THE DESCRIPTION

[0000] This list of documents submitted by the applicant was generated automatically and is included solely for the convenience of the reader. This list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions. Cited patent literature

[0000] DE 384 0 268 C1

[0002] EP 2 815 130 B1

[0003]

Claims

[1] Guide device (1) for extending a fan (2) with a fan housing (3), in particular a radial fan, characterized by that the guide device (1) has several guide elements (4) for influencing the air flow leaving the fan (2). [2] Guide device (1) according to claim 1, characterized by that the guide elements (4) are arranged radially outside or at least in the radially outer region of the fan in the fan housing (3) or in a guide element receptacle, particularly preferably in the case of radial or diagonal fans. [3] Guide device (1) according to one of claims 1 or 2, characterized by that the guide elements (4) are adjustable or changeable, in particular pivotable at an angle of attack (46) about an axis (5) fastened or formed in the fan housing (3) or in a guide element holder. [4] Guide device (1) according to claim 3, characterized bythat the guide elements (4) are not all uniformly the same, but are individually adjustable or changeable to varying degrees. [5] Guide device (1) according to one of claims 3 or 4, characterized by that the guide elements (4) are variable in their length (42) and / or axial depth, in particular telescopically. [6] Guide device (1) according to one of claims 3 to 5, characterized by that the guide elements (4) can be cambered to change their overall shape in a stronger or less pronounced manner and / or can be specifically changed with respect to the reference angles of curvature angle (44) and / or flank angle (45) and / or tip end angle (48) and / or blunt entry angle (49). [7] Guide device (1) according to one of the preceding claims, characterized by that the number of guide elements (4) corresponds approximately to two to three times the number of blades of the fan (2). [8] Ventilation device (6), in particular for installation in a flow duct, particularly preferably for installation in a flow duct of the room air technology, comprising a turbo machine with at least one fan (2) and at least one diffuser, characterized by that at least one guide device according to one of claims 1 to 7 is used as a diffuser. [9] Ventilation device (6), in particular according to claim 8, characterized by that a data processing system is integrated or connected, with an installed computer program that controls an adjustment and / or change of guide elements (4) by means of artificial intelligence to the same or individual extent, wherein the artificial intelligence compares experiences of known operating states and current air parameters and calculates control signals for the guide elements (4) therefrom. [10] Method for increasing the efficiency and / or performance of ventilation devices, in particular ventilation devices of air-conditioning systems, wherein a guide device (1) following a fan (2) in the air flow direction, in particular radially outward as a radial extension, influences the air flow, in particular bringing about a swirl reduction. [11] Method according to claim 10, characterized by that the guide device (1) has guide elements (4), and that the guide elements (4) are adjusted and / or modified to influence the air flow, in particular for pressure recovery, in particular using one or more device features of claims 1 to 7. [12] Method according to one of claims 10 or 11, characterized bythat the air flow in the guide device (1) is influenced by means of a computer program which is based on a three-dimensional calculation model which calculates the optimal angle of attack and / or the optimal curvature and / or the optimal extension of guide elements (4). [13] Method according to one of claims 10, 11 or 12, characterized by that a learning system independently and self-adaptively determines an optimal operating point. [14] Use of a guide device (1) arranged radially around a fan (2) as a diffuser. [15] Use according to claim 14, characterized by that the guide device (1) is adjustable depending on the parameter in order to act as an aerodynamic diffuser, in particular by means of at least one of the device features from one of claims 1 to 7. [16] Use of one of the guide devices from claims 1 to 7 with sensors mounted in particular in the fan housing (3) for feeding a database and for use in a self-learning system.

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