Rotor Profile Design for the Twin-Screw Compressor Based on the Normal-Rack Generation Method

2008 ◽  
Vol 130 (4) ◽  
Author(s):  
Yu-Ren Wu ◽  
Zhang-Hua Fong
Keyword(s):  
Helix Angle ◽  
Tooth Profile ◽  
Normal System ◽  
Rotor Profile ◽  
Twin Screw ◽  
Screw Rotor ◽  
Profile Design ◽  
Rotor Tooth ◽  
Rotor Profiles ◽  
Screw Rotors

This paper proposes a method for designing the rotor profiles of twin-screw compressors using a rack defined in the normal plane. All tooth profile segments are explicitly defined as tangent continuous in the normal section to generate a pair of conjugated rotors. Numerical comparisons between the two types of screw rotor tooth profile design, one based on a normal system, the other on an axial system, show the advantages of using the normal-rack generation method (NRGM). Most particularly, this method allows the same hob used for screw rotors to be used to manufacture mating rotors even as the helix angle varies, because in a normal system the circular pitch remains the same. The numerical results also indicate that the rotor tooth thickness generated by the NRGM rack cutter can prevent serious deflection for a variety of helix angles and tooth combinations.

scholarly journals Study on the reverse design of screw rotor profiles based on a B-spline curve

2019 ◽  
Vol 11 (10) ◽  
pp. 168781401988378 ◽  
Author(s):  
Shu Cao ◽  
Xueming He ◽  
Rong Zhang ◽  
Junfeng Xiao ◽  
Guojiang Shi
Keyword(s):  
Fluid Dynamics ◽  
Fluid Simulation ◽  
Screw Compressor ◽  
B Spline ◽  
Spline Curve ◽  
Rotor Profile ◽  
Twin Screw ◽  
Screw Rotor ◽  
Profile Design ◽  
Rotor Profiles

The female/male screw rotor profile design for a twin screw compressor poses challenges such as frequent parameter modification and a difficult-to-build performance test platform, which affect the efficiency of a rotor profile design. To address these problems, a new idea of applying a B-spline curve to a twin screw compressor rotor profile design is proposed in this article. In addition, the design result underwent fluid simulation based on fluid dynamics technology. This method overcomes the aforementioned challenges. As a meshing line has one-to-one mapping relationship with the rotor profile and reflects important performance parameters of the rotor profile, the method of deducing female and male rotor profiles for a twin screw compressor from a meshing line is proposed. Furthermore, the B-spline curve is used as a composition curve of the meshing line to achieve fast local adjustment of the rotor tooth profile. Based on existing rotor profiles, a meshing line is designed via the B-spline curve, and female and male rotor profiles are derived in reverse. The final rotor profile underwent fluid simulation via computational fluid dynamics analysis under various conditions to analyze the pattern of the internal flow field, which is compared with the results from conventional design.

scholarly journals A Novel Engagement-Pixel Tracking Method for Meshing Clearance Layout of Twin-Screw Rotors

2019 ◽  
Vol 2019 ◽  
pp. 1-12
Author(s):  
Jie Lu ◽  
Zhiqin Cai ◽  
Sijie Cai ◽  
Bin Yao ◽  
Binqiang Chen
Keyword(s):  
Normal Vector ◽  
Discrete Point ◽  
Tracking Method ◽  
Rotor Profile ◽  
Twin Screw ◽  
Contact Models ◽  
Novel Method ◽  
Rotor Profiles ◽  
Screw Rotors

The performance of dry twin-screw compressors is primarily affected by the meshing clearance between a pair of meshing rotors. In this paper, a novel method for meshing clearance layout (MCL) is presented. The presented method is based on the engagement-pixel tracking (EPT) technique, which utilizes discrete-pixel curves generated by the two rotors. An algorithm for the proposed method is put forward. Firstly, when the profile of one rotor is known, the discrete point coordinates of the two rotor profiles and their thermal expansion profiles can be obtained. Secondly, the instantaneous contact models of the two rotors at special meshing positions are acquired under pixel coordinate system. Thirdly, through inspecting the pixels on the profile of a rotor and establishing the corresponding normal vector, the meshing clearance of the two rotors is extracted. Then, the meshing clearances can be generated by extracting the boundary pixels on the other rotor profile. Finally, the meshing clearance layout method is proposed. To verify the effectiveness of the presented method, a case study was conducted on a pair of meshing rotors to extract its meshing clearance. It was shown that the proposed method can be used as a tool for evaluating the clearance distribution of actual machined profiles.

Synthesis and Optimization for Rotor Profiles in Twin Rotor Screw Compressors

1998 ◽  
Vol 122 (4) ◽  
pp. 543-552 ◽  
Author(s):  
Shyh-Haur Su ◽  
Ching-Huan Tseng
Keyword(s):  
Contact Line ◽  
Optimization Problems ◽  
Synthesis Method ◽  
Line Length ◽  
Contact Lines ◽  
Rotor Profile ◽  
Twin Screw ◽  
Screw Rotor ◽  
Rotor Profiles ◽  
Parameter Values

This paper proposes a systematic synthesis method for twin-screw rotor profiles for compressors. Both “original generating curves” and “generated curves” are distributed on each rotor profile, and all the geometric parameters of these curves can be determined with satisfying the conditions of continuity in tangency by given only several specific parameter values. The contact lines on rotor surfaces and the blowhole area calculation are also presented. Three cases of optimization problems are shown in this paper and both contact-line length and blowhole area are reduced when letting the contact-line length be the object function with a constraint of blowhole area. [S1050-0472(00)01103-X]

A twin-screw rotor profile design and computational fluid dynamic simulation method

2015 ◽  
Vol 19 (sup8) ◽  
pp. S8-721-S8-726 ◽  
Author(s):  
X. He ◽  
C. Pan ◽  
M. Wu ◽  
X. Ji ◽  
R. Zhang
Keyword(s):  
Dynamic Simulation ◽  
Computational Fluid Dynamic ◽  
Fluid Dynamic ◽  
Computational Fluid Dynamic Simulation ◽  
Simulation Method ◽  
Rotor Profile ◽  
Twin Screw ◽  
Screw Rotor ◽  
Profile Design

Inter-lobe clearance estimation for twin-screw rotor pairs with point-meshing features

2020 ◽  
pp. 095440892097139
Author(s):  
Minh-Thuận Hoàng ◽  
Yu-Ren Wu
Keyword(s):  
Cad Model ◽  
Screw Pump ◽  
Pump Performance ◽  
Leakage Path ◽  
Rotor Profile ◽  
Shortest Distance ◽  
Twin Screw ◽  
Screw Rotor ◽  
Rotor Profiles ◽  
Solution Accuracy

In practical production, it is impossible even to measure the inter-lobe (meshing) clearance of a screw rotor pair. However, understanding of the clearance distribution is essential since it is a major leakage path which greatly affects the twin-screw pump performance. Previous publications did not disclose explicit detail on how to calculate the meshing clearance for screw rotor pairs with point-meshing features. Therefore, this study proposes a meshing clearance calculation method for screw rotor pairs with point-meshing features. The complex meshing clearance can be simply determined by calculating the shortest distance between two normal-rack profiles generated using point-enveloping principle. Clearance distributions are much more intelligible to be exhibited on a 3-D contact line and the rotor profile. Due to its immeasurability in practice, the adaptability and the solution accuracy of the proposed numerical method are verified by applications on different rotor profiles and comparisons with measured results from a 3-D CAD model. The meshing clearance in a variable-pitch screw rotor pair and the clearance adjustability are also illustrated through the proposed examples.

Development and Optimization of Screw Machines With a Simulation Model—Part I: Profile Generation

1997 ◽  
Vol 119 (3) ◽  
pp. 659-663 ◽  
Author(s):  
N. Stosˇic´ ◽  
K. Hanjalic´
Keyword(s):  
Conjugacy Condition ◽  
Positive Displacement ◽  
Rotor Profile ◽  
Twin Screw ◽  
Compression And Expansion ◽  
Screw Rotor ◽  
Differential Algorithm ◽  
Rotor Profiles ◽  
Generation Procedure ◽  
Thermodynamic Processes

This paper presents a method for the design of twin screw compressors and expanders, which is based on a differential algorithm for defining the rotor profiles and an analytical model of the fluid flow and thermodynamic processes within the machine. Part I of the paper describes the algorithm for screw rotor profile generation. It demonstrates the conjugacy condition which, when solved explicitly, enables a variety of primary arcs to be defined either analytically or by discrete point curves. Its use greatly simplifies the design since only primary arcs need to be specified and these can be located on either the main or gate rotor or even on any other rotor including a rack, which is a rotor of infinite radius. Secondary arcs are then generated automatically from this. By such means any profile combination may be considered. The most efficient were obtained from a combined rotor-rack generation procedure. An example of this combination is given which produces a rotor profile with stiff lobes and a higher throughput than any other known type. Part II describes a mathematical model of the compression and expansion processes within positive displacement machines which has been well proven in its use for the design of reciprocating and screw compressors and screw expanders.

Study on the effects of tooth profile design parameters of rotor to performance of vacuum pump

2020 ◽  
Vol 34 (22n24) ◽  
pp. 2040141
Author(s):  
Van-The Tran ◽  
Bui Trung Thanh ◽  
Banh Tien Long ◽  
Hoang Quoc Tuan ◽  
Duc Toan Nguyen
Keyword(s):  
Vacuum Pump ◽  
Tooth Profile ◽  
Design Parameters ◽  
Tooth Root ◽  
Performance Indices ◽  
Circular Arc ◽  
Numerical Example ◽  
Design Flexibility ◽  
Profile Design ◽  
Rotor Tooth

The vacuum pump usually used traditional curves such as the circular, cycloidal curves and their combinations to construct tooth profile. However, to increase efficiency and design flexibility for the vacuum pump, a novel rotor tooth profile for Roots rotor of vacuum pumps is proposed. Which is named “CEIEC” tooth profile and orderly composed of five significant segments, a circular arc for tooth tip, an epicycloid curve with variable extension, an involute, an enveloped epicycloid curve and a conjugated circular arc for tooth root. A numerical example is presented to evaluate the performance indices for proposed vacuum pump, including the hermeticity coefficients of the rotor mesh gap and tip gap.

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