# The Effect of the Isolator Design on the Efficiency of Rotary Piston Compressors

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## Abstract

**:**

## 1. Introduction

## 2. Materials and Methods

## 3. Results

#### 3.1. Proposed Solution

#### 3.2. Initial Geometries

#### 3.3. Alternative Geometries

## 4. Experimental Setup and Validation

## 5. Discussion

## 6. Conclusions

## Author Contributions

## Funding

## Data Availability Statement

## Acknowledgments

## Conflicts of Interest

## References

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**Figure 1.**The piston-rotor position near the end of the compression process (some degrees before the primary peak pressure is developed).

**Figure 4.**(

**A**) the moment the primary (5) peak pressure is reached during the operating cycle and (

**B**) the moment the secondary (6) peak pressure is reached during the operating cycle.

**Figure 8.**The original (

**A**) and modified design ((

**B**) = 3D printing design with the extra, secondary cavity (7)).

**Figure 11.**(

**A**) End of compression process with original design (primary peak pressure); (

**B**) End of compression process with modified design (primary peak pressure).

**Figure 12.**(

**A**) The secondary peak pressure contour plot of the original design of the geometry; (

**B**) The secondary peak pressure contour plot of the modified geometry.

**Figure 13.**(

**A**) The alternative geometry with the extended cavity, called 4.1; (

**B**) The alternative geometry with the extended cavity, called 4.2.

**Figure 14.**(

**A**) The alternative geometry with the extended cavity, called 4.3; (

**B**) The alternative geometry with the extended cavity, called 4.4.

**Figure 15.**Pressure developed around the secondary peak pressure point for the four different designs.

**Figure 16.**The final assembly of the rotary piston compressor and photographs from the experimental campaign.

Φ = Pressure (Pa) | |
---|---|

N_{1} (×10^{6}) | 4 |

N_{2} (×10^{6}) | 2 |

N_{3} (×10^{6}) | 1 |

GCI^{21} | 0.093% |

GCI^{23} | 0.78% |

Setup | Parameters |
---|---|

Solver | Navier–Stokes density-based |

Pressure inlet (bar) | 1.01 |

Temperature inlet (K) | 300 |

Fluid flow assumption | Redlich-Kwong equation/compressible gas |

Material | Air |

Wall properties | Absolute roughness = 0 |

Models | RNG k-ε, RANS |

Solution method scheme | Transient |

Convergence criterion | PISO/Tolerance: ${10}^{-3}$ |

Primary Peak Pressure | Secondary Peak Pressure | |||
---|---|---|---|---|

Pressure (Bar) | Crank Angle Degree (Deg) | Pressure (Bar) | Crank Angle Degree (Deg) | |

Modified Design | 18.39 | 313.51 | 6.18 | 339.4 |

Original Design | 17.74 | 313.51 | 10.41 | 334.5 |

Design | Pressure (bar) | Temperature (K) | Crank Angle Degree (deg) |
---|---|---|---|

4.0 | 6.18 | 515.8 | 339.4 |

4.1 | 6.47 | 530.24 | 324.6 |

4.2 | 5.35 | 507.43 | 333.4 |

4.3 | 7.07 | 547.54 | 324.4 |

4.4 | 4.52 | 481.76 | 333.4 |

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**MDPI and ACS Style**

Savvakis, S.; Dimopoulou, G.; Zoumpourlos, K.
The Effect of the Isolator Design on the Efficiency of Rotary Piston Compressors. *Thermo* **2023**, *3*, 216-231.
https://doi.org/10.3390/thermo3020013

**AMA Style**

Savvakis S, Dimopoulou G, Zoumpourlos K.
The Effect of the Isolator Design on the Efficiency of Rotary Piston Compressors. *Thermo*. 2023; 3(2):216-231.
https://doi.org/10.3390/thermo3020013

**Chicago/Turabian Style**

Savvakis, Savvas, Georgia Dimopoulou, and Konstantinos Zoumpourlos.
2023. "The Effect of the Isolator Design on the Efficiency of Rotary Piston Compressors" *Thermo* 3, no. 2: 216-231.
https://doi.org/10.3390/thermo3020013