Behavior of MRF Approach on Flow Rate, for the Blower Having
Four Anti Fouling Blades & By Changing the Angular Orientation of
the Blower about the Axis of Rotation
Vikas D Pawar
CFD - Analyst GTEC Whirlpool of India Ltd. D, Block, Weikfield IT Citi Info Park Pune - Nagar Rd., Pune – 411 014, INDIA
[email protected] Ph.:+91- 020 – 66056380
K. Murali Krishna
CFD - Lead Engineer GTEC Whirlpool of India Ltd. D, Block, Weikfield IT Citi Info Park Pune - Nagar Rd., Pune – 411 014, INDIA [email protected]
Ph.: +91- 020 – 66056339
Keywords: CFD, MRF, Blower Angular Orientation
Abstract
The main purpose of this work is to evaluate the effect of angular orientation of a blower on flow rate in MRF approach. The blower is having four 900 symmetry anti-fouling blades. So the relative position of these blades with reference to stationary parts
is changing with its angular orientation. The effect of this relative position on flow rate is evaluated in this present study. As MRF approach assumes one particular angular orientation of blower, the effect of 900 symmetry blades is evaluated by turning blower
in steps of 150 about its axis of rotation. This study shows impact of orientations of such blades on flow rate (around 4%).
Also another study has been done on same blower without anti-fouling blades at two different angular orientations. This shows negligible impact on flow rate. So the studies carried out shows robustness of Acusolve MRF Approach with respect to blower angular orientation.
Introduction:
The dryer provides a fast and convenient method of drying wet clothes especially when space for drying outdoors is limited. The power consumption of conventional dryers is large and frequently the largest component of domestic power cut. So the heat pump dryer is one of the solutions to reduce power consumption. The heat pump dryer employs a refrigeration system, which acts as heat pump.
The wet clothes are kept in a rotating drum and hot air is blown over these clothes. The hot & moist air from rotating drum is pulled by blower and flown through heat exchanger component of heat pump system where it loses its heat and moisture. Then this cold dry air flows through the next heat exchanger component of heat pump system where it gains heat. Then this hot dry air enters the rotating drum through small holes and the cycle is repeated for certain time.
The blower used for this study is of Heat Pump Dryer. The blower has four 900 symmetry anti fouling
blower. As MRF approach assumes one particular angular position, so to consider 900 symmetricity,
the current blower is turned in steps of 150 about its axis of rotation. Five different orientations are
obtained and simulated using Acusolve by MRF approach.
Process Methodology:
The virtual geometry is modeled by considering only basement geometry as shown in Figure 1. The model is prepared by using the Pro-e modeling software. The meshing & pre-processing is performed using Fluid Connection. The blower (shown in Figure 2) is modeled using multiple reference frame method. The heat pump system’s components are modeled as porous regions. Their porous coefficients are calculated from available experimental pressure drop data. The steady simulation has run in Acusolve software and post-processed using Field view software packages.
Figure 1: Computational Domain Figure 2: Blower
Fluid connection software is an unstructured, tetrahedral mesh generator. The mesh generated by Fluid connection is automatic based on the defined parameter of the mesh. Further, pre-processing is performed by defining the appropriate solving parameters and boundary conditions in Fluid Connection. Fluid Connection prepares the input deck required for solving the given problem in AcuSolve.
AcuSolve is one of the commercial CFD software to perform virtual analysis to drive the design & development of the many engineering systems. Some of the features of Solver which makes it unique are --
Analyze Large Systems: AcuSolve with its parallelizing capability can handle systems involving few
components to very large components. The solver is robust and solving time is quite fast. Many of the times each single component in the system may have very large impact on the complete system performance. So, it is always required & desired to understand the complete system behavior rather than the localized behavior. Under such situations AcuSolve provides a very good directional solution.
Physics Capture: AcuSolve a single phase solver is very accurate & stable in solving the systems
involving fluid flow & Thermal interactions. The solver is capable of handling fluid driving systems such as pumps /blowers along with porous media flow. Further, the solver is capable of handling CHT with surface to surface radiation. These features of solver aids in prediction & resolving many engineering issues concerning flow & thermal performance, system efficiency, safety , etc…
Solver Performance: AcuSolve is very robust, stable and accurate compare to other solvers. The
solver has fare flexibility with mesh quality & order of the discretisation Schemes.
Results & Discussions:
As mentioned earlier, the primary focus of the present work is to evaluate the behavior of MRF approach for different blower angular orientations. The results of present study are outlined below,
1. Variation in Flow Rate With Blower Orientations:
Figure 3: Flow Rate Variation with Blower Orientations
Flow rate at 450 Orientation is maximum, whereas 150 Orientation gives minimum flow rate.
Average effect of anti-fouling blades orientation is in agreement with experimental results (around 5%).
2. Velocity and Velocity Vector Plots Over the plane in Z direction
Figure 4: Flow Rate Variation with Blower Orientations 3. Comparison of pressure drop across each component:
Pressure drop across each component at respective flow rate, calculated in CFD is in agreement with that in experimental.
Benefits Summary:
The present study forms basis for further evaluation of blower designs. An experimental testing involves very huge cost. Further the designer need not constraint his ideas to verify the design concepts. The amount of cost and time involved in failure of design in virtual simulation is quite low to that incurred in experimental failure.
Future Plan:
The current methodology can be implemented for further evaluation of blower designs.
Conclusion:
The studies carried out shows robustness of AcuSolve MRF Approach with respect to blower angular orientation. The virtual testing is always beneficial over the experimental testing.
Acknowledgments:
I would like to thank Whirlpool of India Ltd., & Altair India ltd., for supporting me to perform and present this work.
Nomenclature:
MRF Multiple Reference Frame
CFD Computational Fluid Dynamics
References:
1. Anderson John D Jr., 1995, “Computational Fluid Dynamics”, McGraw Hill Publication
2. Cengel Yunus A and John M. Cimbala, 2007, “Fluid Mechanics”, 9th edition, Tata McGraw Hill Publication 3. Manuals of ACUSIM product solver
