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Papers by Rauno Holopainen

International Journal of Ventilation, 2010

The governing equations in duct system flow analyses are nonlinear, and iterative solution method... more The governing equations in duct system flow analyses are nonlinear, and iterative solution methods must be used. A suitable initial flow rate guess may be needed to start the calculations so that a converged solution can be finally achieved. A method to obtain a reasonably accurate initial flow rate guess is presented. In it the duct system is analyzed first in a strongly simplified setting assuming a linear (imaginary laminar) duct flow problem. The continuity equations at the junctions are satisfied. This first initial flow rate guess is then scaled to arrive at a more realistic final initial guess. The scaling is achieved by multiplication by a so–called balancing factor which is based on the application of mechanical energy balance for the whole duct system. The junction continuity equations are still satisfied for this final initial guess. A MATLAB program was generated to perform the calculations. Two demonstration example cases are presented to show the effect of the accuracy...

Työterveyslaitos eBooks, 2012

The aim of this experiment was to study the effect of air duct cleaning on the indoor air quality... more The aim of this experiment was to study the effect of air duct cleaning on the indoor air quality. Three buildings in the Helsinki metropolitan area were selected for the study. In two of the test buildings the ducts were cleaned using three different cleaning methods. The third building serves as a control where no cleaning was done. The air handling systems in the test buildings had operated 26 and 30 years without cleaning. The air quality in the buildings was evaluated by using a trained sensory panel, and tested by the occupants in all these buildings by repeating self-administered questionnaires before and after the cleaning. A trained sensory panel was used to evaluate perceived air quality. The effect of cleaning on the amount of dust in duct system was measured with an optical.method. The amount of dust decreased significantly in all the cleaning methods. Significant differences in the cleaning results between the three cleaning methods were observed. The cleaning of supply...

Spearman rank-order correlations between dust load (g/m2 of carpet) and microbial concentrations ... more Spearman rank-order correlations between dust load (g/m2 of carpet) and microbial concentrations (CE/mg) in carpet dust versus particulate matter (μg/m3 of sampled air) and microbial concentrations (CE/m3 of sampled air) in the infant breathing zone during crawling experiments on 17 carpets. Microbial concentrations were determined with qPCR. (PNG 58 kb)

Part of a series of fi ve reports that cover energy and industry, traffi c and transport, measure... more Part of a series of fi ve reports that cover energy and industry, traffi c and transport, measurement technology, indoor air, and health and the environment. This publication includes material protected under copyright law, the copyright for which is held by Tekes or a third party. Material contained here may not be used for commercial purposes. The contents are the opinion of the writers concerned and do not represent the offi cial Tekes position. Tekes bears no responsibility for any possible damage arising from the use of this material. The original source must be mentioned when quoting from this publication. 3 Preface T he air we breathe exposes us to a growing number of airborne contaminants, including particulate matter invisible to the eye, as a result of ever-growing traffi c volumes and ever-higher levels of energy generation , as well as other factors. Fine particulates are known to have major health implications, and result in the premature death of over 300,000 people in...

Rakenteiden Mekaniikka

Artikkelin aiheena on painovoimaisen ilmanvaihdon soveltaminen hormi-tyyp­pi­siin aukkoihin käytt... more Artikkelin aiheena on painovoimaisen ilmanvaihdon soveltaminen hormi-tyyp­pi­siin aukkoihin käyttäen hyväksi mekaanisen energian taseen periaatetta. Kanavisto-virtauksen kä­sit­teen häviökerroin yhteys painovoimaisen ilmanvaihdon käsitteeseen purkautumiskerroin tu­lee esille. Kontrollitilavuustarkastelut ovat tärkeässä asemassa. Kaksi yksinkertaista esi­merk­ki­tapausta esitetään. Artikkeli on aiheeltaan opetuksellinen.

Sairaaloiden leikkausaleissa muodostuu kaasumaisia ja hiukkasmaisia epäpuhtauksia leikkaustoimenp... more Sairaaloiden leikkausaleissa muodostuu kaasumaisia ja hiukkasmaisia epäpuhtauksia leikkaustoimenpiteiden aikana. Epäpuhtauksien poistamiseen on olemassa erilaisia kohdepoistojärjestelmiä. Opinnäytetyönä tehdyn tutkimuksen tavoitteena oli selvittää leikkaussaleissa tyypillisesti käytössä olevat kohdepoistojärjestelmät, niiden tehokkuus ja käytettävyys. Tutkimus toteutettiin haastattelemalla leikkaussalien henkilökuntaa ja hakemalla viimeisimpiä tutkimustuloksia kirjallisuudesta. Lisäksi tehtiin epäpuhtauslaskelmia leikkaussalin anestesiakaasu- ja hiukkaspitoisuuksista. Haastatteluihin pyydettiin viiden sairaanhoitopiirin LVI-asiantuntijoita ja leikkaussalihenkilökuntaa. Kirjallisuudessa esitettyjen tutkimustulosten perusteella käytössä olevilla kohdepoistoratkaisuilla saadaan tehokkaasti poistettua diatermian käytössä syntyvää savua ja operaatiossa syntyviä anestesiakaasuvuotoja. Taselaskelmien perusteella voidaan todeta, että anestesiakaasuvuotojen ensisijainen poistaminen kohdepois...

Journal of Fundamentals of Renewable Energy and Applications, 2015

Latin symbols total heat transfer surface area () specific heat at constant pressure () relative ... more Latin symbols total heat transfer surface area () specific heat at constant pressure () relative error estimate (−) overall heat transfer coefficient () length of storage unit () mass () mass rate of fluid flow () period time length () effective convergence rate (−) dimensionless temperature (−) temperature (,) axial coordinate () Greek symbols nondimensional time coordinate (−) thermal ratio (−) reduced length (−) grid refinement ratio (−) nondimensional position coordinate (−)

The article concerns the treatment of junctions when teaching duct system flows. In standard flui... more The article concerns the treatment of junctions when teaching duct system flows. In standard fluid mechanics textbook presentations only one static pressure value is usually associated with a junction. In engineering practice, however, pressure jumps over the junctions should be taken into account. The differences in the results by these two formulations are discussed in connection with three demonstration cases. The first case is treated initially with assumed constant friction factors so that closed form classroom hand calculations can be performed. More accurate numerical results are then obtained by a MATLAB program. The concept of a spurious dissipation is introduced to explain the apparently odd differences obtained by the two formulations.

This paper reports the comparison of three measuring methods for quantifying the amount of dust o... more This paper reports the comparison of three measuring methods for quantifying the amount of dust on the inner surface of ventilation ducts: 1) a vacuum test method; 2) a gravimetric tape method; and 3) an optical method. Thirteen recently constructed buildings were selected for the field test in the Helsinki metropolitan area. The dust samples in each method were all taken from the same location in the duct. Most of the ducts sampled had no residual oil originating from the manufacturing process. The mean amount of dust measured with the vacuum test method was 1.3 g/m 2 and the range was Ͻ0.1-8.4 g/m 2 . The mean surface dust level measured using the gravimetric tape method was slightly lower, i.e. 1.2 g/m 2 (Ͻ0.1-5.0 g/m 2 ). The mean cleanliness level of the ducts was 15% (2-41%) using the optical method. The wide variations and differences in the results of the different methods were caused by the unequal distribution of dust on the duct surfaces. Key words HVAC system; Duct; Dust...

International Journal of Ventilation

Abstract When the airflow pressure losses at the junctions of ducts in ventilation systems aretak... more Abstract When the airflow pressure losses at the junctions of ducts in ventilation systems aretaken into account, the analysis becomes more complicated since no unique value for the static pressure is associated with a junction. Additional system equations expressing the pressure jumps over the junctions must be written down. A method to replace the junction losses approximately as equivalent channel section losses is presented. The method isbased on dissipation considerations. Simpler system equations with fewer unknowns are obtained. Some example cases are presented to give an idea about the errors involved.

International Journal of Ventilation, 2010

Application of the principle of the balance of mechanical energy gives a constraint on the possib... more Application of the principle of the balance of mechanical energy gives a constraint on the possible values of the junction coefficients at a duct system junction. In some cases the recorded junction coefficients in the literature do not satisfy this constraint. The values given may then be questionable. The terminology in connection with junctions is discussed and the role of the principle of balance of mechanical energy in duct system flow modelling is considered in some detail.

Summary. The article concerns the treatment of junctions when teaching duct system flows. In stan... more Summary. The article concerns the treatment of junctions when teaching duct system flows. In standard fluid mechanics textbook presentations only one static pressure value is usually associated with a junction. In engineering practice, however, pressure jumps over the junctions should be taken into account. The differences in the results by these two formulations are discussed in connection with three demonstration cases. The first case is treated initially with assumed constant friction factors so that closed form classroom hand calculations can be performed. More accurate numerical results are then obtained by a MATLAB program. The concept of a spurious dissipation is introduced to explain the apparently odd differences obtained by the two formulations.

International Journal of Ventilation, 2010

The governing equations in duct system flow analyses are nonlinear, and iterative solution method... more The governing equations in duct system flow analyses are nonlinear, and iterative solution methods must be used. A suitable initial flow rate guess may be needed to start the calculations so that a converged solution can be finally achieved. A method to obtain a reasonably accurate initial flow rate guess is presented. In it the duct system is analyzed first in a strongly simplified setting assuming a linear (imaginary laminar) duct flow problem. The continuity equations at the junctions are satisfied. This first initial flow rate guess is then scaled to arrive at a more realistic final initial guess. The scaling is achieved by multiplication by a so–called balancing factor which is based on the application of mechanical energy balance for the whole duct system. The junction continuity equations are still satisfied for this final initial guess. A MATLAB program was generated to perform the calculations. Two demonstration example cases are presented to show the effect of the accuracy...

Työterveyslaitos eBooks, 2012

The aim of this experiment was to study the effect of air duct cleaning on the indoor air quality... more The aim of this experiment was to study the effect of air duct cleaning on the indoor air quality. Three buildings in the Helsinki metropolitan area were selected for the study. In two of the test buildings the ducts were cleaned using three different cleaning methods. The third building serves as a control where no cleaning was done. The air handling systems in the test buildings had operated 26 and 30 years without cleaning. The air quality in the buildings was evaluated by using a trained sensory panel, and tested by the occupants in all these buildings by repeating self-administered questionnaires before and after the cleaning. A trained sensory panel was used to evaluate perceived air quality. The effect of cleaning on the amount of dust in duct system was measured with an optical.method. The amount of dust decreased significantly in all the cleaning methods. Significant differences in the cleaning results between the three cleaning methods were observed. The cleaning of supply...

Spearman rank-order correlations between dust load (g/m2 of carpet) and microbial concentrations ... more Spearman rank-order correlations between dust load (g/m2 of carpet) and microbial concentrations (CE/mg) in carpet dust versus particulate matter (μg/m3 of sampled air) and microbial concentrations (CE/m3 of sampled air) in the infant breathing zone during crawling experiments on 17 carpets. Microbial concentrations were determined with qPCR. (PNG 58 kb)

Part of a series of fi ve reports that cover energy and industry, traffi c and transport, measure... more Part of a series of fi ve reports that cover energy and industry, traffi c and transport, measurement technology, indoor air, and health and the environment. This publication includes material protected under copyright law, the copyright for which is held by Tekes or a third party. Material contained here may not be used for commercial purposes. The contents are the opinion of the writers concerned and do not represent the offi cial Tekes position. Tekes bears no responsibility for any possible damage arising from the use of this material. The original source must be mentioned when quoting from this publication. 3 Preface T he air we breathe exposes us to a growing number of airborne contaminants, including particulate matter invisible to the eye, as a result of ever-growing traffi c volumes and ever-higher levels of energy generation , as well as other factors. Fine particulates are known to have major health implications, and result in the premature death of over 300,000 people in...

Rakenteiden Mekaniikka

Artikkelin aiheena on painovoimaisen ilmanvaihdon soveltaminen hormi-tyyp­pi­siin aukkoihin käytt... more Artikkelin aiheena on painovoimaisen ilmanvaihdon soveltaminen hormi-tyyp­pi­siin aukkoihin käyttäen hyväksi mekaanisen energian taseen periaatetta. Kanavisto-virtauksen kä­sit­teen häviökerroin yhteys painovoimaisen ilmanvaihdon käsitteeseen purkautumiskerroin tu­lee esille. Kontrollitilavuustarkastelut ovat tärkeässä asemassa. Kaksi yksinkertaista esi­merk­ki­tapausta esitetään. Artikkeli on aiheeltaan opetuksellinen.

Sairaaloiden leikkausaleissa muodostuu kaasumaisia ja hiukkasmaisia epäpuhtauksia leikkaustoimenp... more Sairaaloiden leikkausaleissa muodostuu kaasumaisia ja hiukkasmaisia epäpuhtauksia leikkaustoimenpiteiden aikana. Epäpuhtauksien poistamiseen on olemassa erilaisia kohdepoistojärjestelmiä. Opinnäytetyönä tehdyn tutkimuksen tavoitteena oli selvittää leikkaussaleissa tyypillisesti käytössä olevat kohdepoistojärjestelmät, niiden tehokkuus ja käytettävyys. Tutkimus toteutettiin haastattelemalla leikkaussalien henkilökuntaa ja hakemalla viimeisimpiä tutkimustuloksia kirjallisuudesta. Lisäksi tehtiin epäpuhtauslaskelmia leikkaussalin anestesiakaasu- ja hiukkaspitoisuuksista. Haastatteluihin pyydettiin viiden sairaanhoitopiirin LVI-asiantuntijoita ja leikkaussalihenkilökuntaa. Kirjallisuudessa esitettyjen tutkimustulosten perusteella käytössä olevilla kohdepoistoratkaisuilla saadaan tehokkaasti poistettua diatermian käytössä syntyvää savua ja operaatiossa syntyviä anestesiakaasuvuotoja. Taselaskelmien perusteella voidaan todeta, että anestesiakaasuvuotojen ensisijainen poistaminen kohdepois...

Journal of Fundamentals of Renewable Energy and Applications, 2015

Latin symbols total heat transfer surface area () specific heat at constant pressure () relative ... more Latin symbols total heat transfer surface area () specific heat at constant pressure () relative error estimate (−) overall heat transfer coefficient () length of storage unit () mass () mass rate of fluid flow () period time length () effective convergence rate (−) dimensionless temperature (−) temperature (,) axial coordinate () Greek symbols nondimensional time coordinate (−) thermal ratio (−) reduced length (−) grid refinement ratio (−) nondimensional position coordinate (−)

The article concerns the treatment of junctions when teaching duct system flows. In standard flui... more The article concerns the treatment of junctions when teaching duct system flows. In standard fluid mechanics textbook presentations only one static pressure value is usually associated with a junction. In engineering practice, however, pressure jumps over the junctions should be taken into account. The differences in the results by these two formulations are discussed in connection with three demonstration cases. The first case is treated initially with assumed constant friction factors so that closed form classroom hand calculations can be performed. More accurate numerical results are then obtained by a MATLAB program. The concept of a spurious dissipation is introduced to explain the apparently odd differences obtained by the two formulations.

This paper reports the comparison of three measuring methods for quantifying the amount of dust o... more This paper reports the comparison of three measuring methods for quantifying the amount of dust on the inner surface of ventilation ducts: 1) a vacuum test method; 2) a gravimetric tape method; and 3) an optical method. Thirteen recently constructed buildings were selected for the field test in the Helsinki metropolitan area. The dust samples in each method were all taken from the same location in the duct. Most of the ducts sampled had no residual oil originating from the manufacturing process. The mean amount of dust measured with the vacuum test method was 1.3 g/m 2 and the range was Ͻ0.1-8.4 g/m 2 . The mean surface dust level measured using the gravimetric tape method was slightly lower, i.e. 1.2 g/m 2 (Ͻ0.1-5.0 g/m 2 ). The mean cleanliness level of the ducts was 15% (2-41%) using the optical method. The wide variations and differences in the results of the different methods were caused by the unequal distribution of dust on the duct surfaces. Key words HVAC system; Duct; Dust...

International Journal of Ventilation

Abstract When the airflow pressure losses at the junctions of ducts in ventilation systems aretak... more Abstract When the airflow pressure losses at the junctions of ducts in ventilation systems aretaken into account, the analysis becomes more complicated since no unique value for the static pressure is associated with a junction. Additional system equations expressing the pressure jumps over the junctions must be written down. A method to replace the junction losses approximately as equivalent channel section losses is presented. The method isbased on dissipation considerations. Simpler system equations with fewer unknowns are obtained. Some example cases are presented to give an idea about the errors involved.

International Journal of Ventilation, 2010

Application of the principle of the balance of mechanical energy gives a constraint on the possib... more Application of the principle of the balance of mechanical energy gives a constraint on the possible values of the junction coefficients at a duct system junction. In some cases the recorded junction coefficients in the literature do not satisfy this constraint. The values given may then be questionable. The terminology in connection with junctions is discussed and the role of the principle of balance of mechanical energy in duct system flow modelling is considered in some detail.

Summary. The article concerns the treatment of junctions when teaching duct system flows. In stan... more Summary. The article concerns the treatment of junctions when teaching duct system flows. In standard fluid mechanics textbook presentations only one static pressure value is usually associated with a junction. In engineering practice, however, pressure jumps over the junctions should be taken into account. The differences in the results by these two formulations are discussed in connection with three demonstration cases. The first case is treated initially with assumed constant friction factors so that closed form classroom hand calculations can be performed. More accurate numerical results are then obtained by a MATLAB program. The concept of a spurious dissipation is introduced to explain the apparently odd differences obtained by the two formulations.