RP-1245 -- Determining the Effects of Duct Fittings on Volumetric Air Measurements

This final report discusses the experimental setup, testing procedures, and testing results of ASHRAE Research Project 1245-RP, sponsored by TC1.2 (Instruments and Measurements) and TC7.7 (Testing and Balancing). The purpose of the research was to quantify the influence of several duct disturbances on volumetric flow rate measurements and to develop guidelines for field technicians, to assist them in making more accurate volumetric air flow measurements in rectangular ducts during test and balance operations. Multiple duct sizes, fitting disturbances, velocity probes, traverse algorithms, and locations upstream and downstream of the disturbances were used in this research. The two traverse algorithms used were the Log-Tchebycheff (LT) method and Equal Area (EA) method. Two upstream and five downstream locations were tested for each duct configuration. Two air velocity probes, a Pitot-static probe and a hot wire anemometer probe, were used for local velocity measurements on each traverse: A nozzle bank and Air Flow Measurement Station was used as the flow measurement standards for comparison with each traverse measurement.

The report is organized into separate Chapters and Appendices. Chapter 1 gives a detailed description of the project and objectives and a review of relevant background material. Chapter 2 describes the experimental facility. Chapter 3 describes the methods of determining volumetric flow rate used in this research, and discusses the determination of relevant air properties. Chapter 4 presents the experimental procedures used in this research. A detailed experimental uncertainty analysis is given in Chapter 5. Chapter 6 presents the experimental test results along with analysis of these results. Conclusions and general recommendations are given in Chapter 7. Appendix A gives leak test results. Appendix B, C, and D contain graphical and tabular experimental results for the 24x24, 48x12 and 28x14 duct sizes tested. Sample calculations are give in Appendix E. Instrument calibrations are given in Appendix F, and instrument technical specifications are given in Appendix G. LabView front panels and block diagrams are given in Appendix H. Appendix I, J and K contain summary tables for all tests conducted. Appendix L gives all graphical tee results. Appendix M contains two CFD simulation honors research projects. Appendix N contains the original RFP for this project.



Product Code(s): D-RP-1245