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<?xml-stylesheet type="text/xsl" href="https://communities.bentley.com/cfs-file/__key/system/syndication/rss.xsl" media="screen"?><rss version="2.0" xmlns:dc="http://purl.org/dc/elements/1.1/" xmlns:slash="http://purl.org/rss/1.0/modules/slash/" xmlns:wfw="http://wellformedweb.org/CommentAPI/"><channel><title>How to include Mass Transfer Coefficient into MSX</title><link>https://communities.bentley.com/products/hydraulics___hydrology/f/haestad-hydraulics-and-hydrology-forum/184927/how-to-include-mass-transfer-coefficient-into-msx</link><description>Hi Everyone, 
 We&amp;#39;re currently working on developing an MSX model for Chlorine Decay that can account for wall decay as a factor of Biofilm growth (thus removing the need to specify wall decay for specific pipes throughout the network). 
 Unfortunately</description><dc:language>en-US</dc:language><generator>Telligent Community 12</generator><item><title>RE: How to include Mass Transfer Coefficient into MSX</title><link>https://communities.bentley.com/thread/548148?ContentTypeID=1</link><pubDate>Fri, 11 Oct 2019 06:37:43 GMT</pubDate><guid isPermaLink="false">6dad98f5-dbc9-4c4d-a9ba-e9da8dc6aa8e:35813034-8787-47da-b41c-1867d3cc5768</guid><dc:creator>Yashodhan Joshi</dc:creator><description>&lt;p&gt;The above solution is now included as a wiki article as below;&lt;/p&gt;
&lt;p&gt;&lt;a title="How to include result fields or pre-defined parameters in Multi Species Extension (MSX) for analysis?" href="/products/hydraulics___hydrology/w/hydraulics_and_hydrology__wiki/43712/how-to-include-result-fields-or-pre-defined-parameters-in-multi-species-extension-msx-for-analysis" rel="noopener noreferrer" target="_blank"&gt;How to include result fields or pre-defined parameters in Multi Species Extension (MSX) for analysis?&lt;/a&gt;&lt;/p&gt;&lt;div style="clear:both;"&gt;&lt;/div&gt;</description></item><item><title>RE: How to include Mass Transfer Coefficient into MSX</title><link>https://communities.bentley.com/thread/542379?ContentTypeID=1</link><pubDate>Thu, 05 Sep 2019 22:56:10 GMT</pubDate><guid isPermaLink="false">6dad98f5-dbc9-4c4d-a9ba-e9da8dc6aa8e:24f9bf3b-11b6-46ac-82e3-75ea430309ec</guid><dc:creator>Ryan Catling</dc:creator><description>&lt;p&gt;G&amp;rsquo;day Tom,&lt;/p&gt;
&lt;p&gt;&amp;nbsp;Firstly I would like to start by saying I&amp;rsquo;m aware of the limitations of Chlorine Decay Modelling and I understand it&amp;#39;s questionable whether this process is worth the effort given the limitations of the model.&lt;/p&gt;
&lt;p&gt;An easier method&amp;nbsp;would be&amp;nbsp;to simply;&lt;/p&gt;
&lt;ul&gt;
&lt;li&gt;Analyse the Chlorine consumption of the treated water to develop an understanding of its rate of decay,&lt;/li&gt;
&lt;li&gt;Run a water age analysis of the model, highlighting age since the last chlorine boost across the system (not just total age)&lt;/li&gt;
&lt;li&gt;Use this knowledge of initial and chlorine boosts, combined with chlorine bulk decay and water age (total and since last boost) to identify at risk areas and locations that could potentially be dosed less or may need to be dosed more.&lt;/li&gt;
&lt;li&gt;Run a trial and error dosing adjustment program where doses are slowly adjusted while key points in the system are monitored for chlorine residuals.&lt;/li&gt;
&lt;/ul&gt;
&lt;p&gt;I agree with the&amp;nbsp;benefits of&amp;nbsp;tons of field Cl field data, we don&amp;#39;t have a lot but we do have a reasonable amount.&lt;/p&gt;
&lt;p&gt;We will be re-building our EPS model in the near future, in order to improve our calibration of this we&amp;rsquo;ve installed 20 pressure loggers across the system in addition to all the existing pressure and flow loggers.&lt;/p&gt;
&lt;p&gt;Up to&amp;nbsp;the comment on&amp;nbsp;using the constituent model I agree&amp;nbsp;with everything. But I have to argue strongly against using the WaterGEMS constituent model. We have used this previously&amp;nbsp;and it is incredibly inaccurate. If you&amp;rsquo;re aware of Fishers work you&amp;rsquo;ll understand exactly how inaccurate first order decay is for networks with several day&amp;rsquo;s water age and multiple chlorine boosting stations. I would argue that it can be dangerous to use this because if someone were to use that method and think that it has some degree of accuracy; it could potentially lead to decisions being made that may have significant consequences.&lt;/p&gt;
&lt;p&gt;&amp;nbsp;I like your modeling Quote from George Box, and that&amp;rsquo;s exactly what I&amp;rsquo;m trying to achieve.. A useful Chlorine decay model.&lt;/p&gt;
&lt;p&gt;&lt;/p&gt;
&lt;p&gt;As&amp;nbsp;a side&amp;nbsp;note:&lt;/p&gt;
&lt;p&gt;While many reticulation networks have limited continuous monitoring for pressure, flow and chlorine, as the years go by, the amount of monitoring that occurs across Australia is increasing. Additionally academics are constantly researching and developing new and improved equations to represent the way chemicals interact throughout these systems. With these developments, in conjunction with continual improvements in computer&amp;nbsp;processing power, it&amp;#39;s only a matter of time before everything necessary to run accurate and reliable chlorine decay models exists... and all we would need then is the software to do so :)&lt;/p&gt;&lt;div style="clear:both;"&gt;&lt;/div&gt;</description></item><item><title>RE: How to include Mass Transfer Coefficient into MSX</title><link>https://communities.bentley.com/thread/542292?ContentTypeID=1</link><pubDate>Thu, 05 Sep 2019 13:59:40 GMT</pubDate><guid isPermaLink="false">6dad98f5-dbc9-4c4d-a9ba-e9da8dc6aa8e:844a1c7d-d4fb-4dc9-a41b-b648a06acc17</guid><dc:creator>Tom Walski</dc:creator><description>&lt;p&gt;Ryan, it&amp;#39;s admirable to try to apply MSX to your situation but I prefer to approach things incrementally. I believe it was Einstein who said, &amp;quot;A model should be as simple as possible but no simpler.&amp;quot; That applies here.&lt;/p&gt;
&lt;p&gt;Before I would even start modeling, I would collect tons of field Cl data (with corresponding demands and boundary conditions) and analyze it to determine the nature&amp;nbsp;of the &amp;nbsp;problem and range of solutions. I assume you&amp;#39;ve done this.&lt;/p&gt;
&lt;p&gt;Then I would ensure that my EPS model is very well calibrated. If it&amp;#39;s not almost perfect, then why bother with something like MSX?&lt;/p&gt;
&lt;p&gt;Then I would try to model my chlorine data using the standard WaterGEMS&amp;nbsp;constituent model (not MSX) by adjusting my wall decay rates (increasing them in areas where &amp;nbsp;flows are very low). This may be good enough for what you need and it is much easier than MSX.&lt;/p&gt;
&lt;p&gt;If you are certain that everything in your model is correct, except that the WaterGEMS constituent model is not adequate, only then would I take Wayne&amp;#39;s advice and dive into MSX.&lt;/p&gt;
&lt;p&gt;I&amp;#39;m aware of Fisher&amp;#39;s work and its&amp;#39; quite good.&lt;/p&gt;
&lt;p&gt;If you would like to discuss more off line, send me an email and we can call (&lt;a href="mailto:tom.walski@bentley.com"&gt;tom.walski@bentley.com&lt;/a&gt;).&lt;/p&gt;
&lt;p&gt;I&amp;#39;ll leave you with one more famous saying. Mathematician George Box once said something like,&amp;nbsp;&amp;quot;All models are wrong. Some are useful anyway.&amp;quot;&lt;/p&gt;
&lt;p&gt;Best wishes,&lt;/p&gt;
&lt;p&gt;Tom&lt;/p&gt;&lt;div style="clear:both;"&gt;&lt;/div&gt;</description></item><item><title>RE: How to include Mass Transfer Coefficient into MSX</title><link>https://communities.bentley.com/thread/542166?ContentTypeID=1</link><pubDate>Thu, 05 Sep 2019 07:49:30 GMT</pubDate><guid isPermaLink="false">6dad98f5-dbc9-4c4d-a9ba-e9da8dc6aa8e:bd9b9968-18d4-433e-af9e-bc4e9177ab7d</guid><dc:creator>Wayne Hartell</dc:creator><description>&lt;p&gt;Re: &amp;quot;&lt;span&gt;It would also be great if pipe material and age were terms that could also be referenced in MSX,&amp;quot;&lt;/span&gt;&lt;/p&gt;
&lt;p&gt;&lt;span&gt;Pipe material is not possible right now, but Age is. You could do this by modeling age as a species that does not grow or decay.&lt;/span&gt;&lt;/p&gt;
&lt;p&gt;&lt;span&gt;[SPECIES]&lt;br /&gt;; Age&lt;br /&gt;BULK Age MG&lt;/span&gt;&lt;/p&gt;
&lt;p&gt;&lt;span&gt;[PIPES]&lt;br /&gt;RATE Age 1.0&lt;/span&gt;&lt;/p&gt;
&lt;p&gt;&lt;span&gt;[TANKS]&lt;br /&gt;;Age&lt;br /&gt;RATE Age 1.0&lt;/span&gt;&lt;/p&gt;
&lt;p&gt;[QUALITY]&lt;br /&gt;GLOBAL Age 24.0&lt;/p&gt;
&lt;p&gt;&lt;span&gt;(The last part is just if you want to use an initial age... you can do that globally or by element).&lt;/span&gt;&lt;/p&gt;
&lt;p&gt;&lt;span&gt;The units are just a label and can be ignored, especially if the purpose is just to calculate some other dependent value.&lt;/span&gt;&lt;/p&gt;
&lt;p&gt;&lt;span&gt;In my test model this seems to have the desired outcome.&lt;/span&gt;&lt;/p&gt;
&lt;p&gt;&lt;span&gt;&lt;img alt=" " src="/resized-image/__size/320x240/__key/communityserver-discussions-components-files/5925/Age.jpg" /&gt;&lt;/span&gt;&lt;/p&gt;
&lt;p&gt;&lt;span&gt;Hope this helps.&lt;/span&gt;&lt;/p&gt;
&lt;p&gt;&lt;span&gt;Regards,&lt;/span&gt;&lt;/p&gt;
&lt;p&gt;&lt;span&gt;Wayne.&lt;/span&gt;&lt;/p&gt;&lt;div style="clear:both;"&gt;&lt;/div&gt;</description></item><item><title>RE: How to include Mass Transfer Coefficient into MSX</title><link>https://communities.bentley.com/thread/542154?ContentTypeID=1</link><pubDate>Thu, 05 Sep 2019 07:22:02 GMT</pubDate><guid isPermaLink="false">6dad98f5-dbc9-4c4d-a9ba-e9da8dc6aa8e:90571124-780e-43d8-9dc6-751ed655a0ea</guid><dc:creator>Wayne Hartell</dc:creator><description>&lt;p&gt;Hi Ryan,&lt;/p&gt;
&lt;p&gt;I think there has been some confusion in this thread for which I apologize.&lt;/p&gt;
&lt;p&gt;The first thing to note is that the UDX route won&amp;#39;t work, not because there is anything wrong with UDX (it&amp;#39;s a cool feature), but because there is no way (currently) to plug in UDX fields into the input side of an MSX calculation. (It is possible to do that kind of thing for regular calculations with some programming knowledge, but that is outside the scope of this thread).&lt;/p&gt;
&lt;p&gt;So to re-iterate, it is definitely possible to do what you want using the TERMS feature of MSX just as I initially stated. I think I understand now that what you were missing is not that the terms can be defined as a function of Reynold&amp;#39;s number (and other pre-defined variables), but how to apply different behaviors based on different value ranges of Reynolds Number (i.e., different flow regimes). It wasn&amp;#39;t clear to me that this was the stumbling block based on the way I was reading your responses.&lt;/p&gt;
&lt;p&gt;The key to the application of different formulae to different value ranges of Reynolds Number, or indeed different value ranges of any different kind of variable is the STEP(x) function in MSX. An example of its usage is given on page 62 of the EPANET MSX 1.1 user manual, and it is described on page 63. If you think about it, a tool like MSX wouldn&amp;#39;t have much value if this type of thing was not possible, since it would completely prevent the type of situation you are trying to model from being modeled.&lt;/p&gt;
&lt;p&gt;The step function works as follows (example only; this is not implementing the actual mass transfer coefficient equations you want, just demonstrating the general mechanism by which it can be achieved using MSX).&lt;/p&gt;
&lt;p&gt;Let&amp;#39;s say that you had 3 flow regimes that you were interested in.&lt;/p&gt;
&lt;p&gt;&lt;strong&gt;1: Re &amp;lt;= 1.0e5&lt;/strong&gt;&lt;br /&gt;&lt;strong&gt;2: 1.0e5 &amp;lt; Re &amp;lt;= 1.0e7&lt;/strong&gt;&lt;br /&gt;&lt;strong&gt;3: Re &amp;gt; 1.0e7&lt;/strong&gt;&lt;/p&gt;
&lt;p&gt;You could apply different sets of reaction equations subject to these three regimes.&lt;/p&gt;
&lt;p&gt;First to capture the different flow regimes, you could define new TERMS as follows.&lt;/p&gt;
&lt;p&gt;&lt;strong&gt;[TERMS]&lt;/strong&gt;&lt;br /&gt;&lt;strong&gt;FR1 STEP(1.0e5 - Re) ; Re &amp;lt;= 1.0e5&lt;/strong&gt;&lt;br /&gt;&lt;strong&gt;FR2 STEP(1.0e7 - Re) * (1 - FR1) ; Re &amp;lt;= 1.0e7&lt;/strong&gt;&lt;br /&gt;&lt;strong&gt;FR3 STEP(1.0e9 - Re) * (1 - FR2) ; Re &amp;lt;= 1.0e9&lt;/strong&gt;&lt;br /&gt;&lt;strong&gt;FR1M FR1&lt;/strong&gt;&lt;br /&gt;&lt;strong&gt;FR2M FR2 * 10&lt;/strong&gt;&lt;br /&gt;&lt;strong&gt;FR3M FR3 * 25&lt;/strong&gt;&lt;/p&gt;
&lt;p&gt;The first three terms (FR1, FR2, and FR3) are the flow regimes. These terms evaluate to 1 or 0 depending on whether the pipe flow is within the defined range of Reynolds Number. These could be used directly to &amp;quot;turn on&amp;quot; (or off) various parts of a decay equation thus enabling the ability to define reaction rates that involve different equations for different flow regimes.&lt;/p&gt;
&lt;p&gt;The second three terms (FR1M, FR2M and FR3M) are simply terms (multipliers) that I created to demonstrate that the previous three terms work as expected. We will see how this works in a moment.&lt;/p&gt;
&lt;p&gt;Then to implement the regimes in the equations you&amp;nbsp;simply write equations that leverage the previous terms. (In my example the FR1M, FR2M and FR3M terms; in your case the FR1 FR2 and FR3 terms).&lt;/p&gt;
&lt;p&gt;[PIPES]&lt;br /&gt;;Free chlorine decay&lt;br /&gt;RATE CL2 &lt;strong&gt;FR1M&lt;/strong&gt;*(-Ks20*TC*Cs*CL2-Kf20*TC*Cf*CL2-Km20*TC*Cm*CL2) + &lt;strong&gt;FR2M&lt;/strong&gt;*(-Ks20*TC*Cs*CL2-Kf20*TC*Cf*CL2-Km20*TC*Cm*CL2)+ &lt;strong&gt;FR3M&lt;/strong&gt;*(-Ks20*TC*Cs*CL2-Kf20*TC*Cf*CL2-Km20*TC*Cm*CL2)&lt;/p&gt;
&lt;p&gt;What I am doing above in my example is modifying the CL2 decay rate for pipes subject to the flow regime. The equation above, simplified is:&lt;/p&gt;
&lt;p&gt;RATE CL2 &lt;strong&gt;FR1M&lt;/strong&gt;*Const&amp;nbsp;+ &lt;strong&gt;FR2M&lt;/strong&gt;*Const + &lt;strong&gt;FR3M&lt;/strong&gt;*Const, where Const is the result of all the terms that define the decay rate.&lt;/p&gt;
&lt;p&gt;(In my example I am using the same equation for each multiplier and increasing the decay rate by a factor, but in your case you would likely stick to multipliers of 0 and 1 (FR1, FR2, FR3) to turn on/off parts of the decay rate equation that do not apply to the specific flow regime).&lt;/p&gt;
&lt;p&gt;In&amp;nbsp;my example, and referring to the simplified form of the equation, the outcomes are that:&lt;/p&gt;
&lt;p&gt;...if the flow regime is such that Re &amp;lt; 1.0e5, then the decay rate is 1*Const.&lt;br /&gt;&lt;span&gt;...i&lt;/span&gt;f the flow regime is such that Re &amp;gt; 1.0e5 and Re &amp;lt;= 1.0e7 then the decay rate is 10*Const&lt;br /&gt;&lt;span&gt;...i&lt;/span&gt;f the flow regime is such that Re &amp;gt; 1.0e7 and Re &amp;lt;= 1.0e9 then the decay rate is 25*Const&lt;/p&gt;
&lt;p&gt;In other words, the higher the value of Re (subject to the stepwise evaluation within the defined ranges), the higher the decay rate.&lt;/p&gt;
&lt;p&gt;I know this is not the specific equations you want to implement, but it&amp;#39;s illustrating the underlying mechanism by which you, or anyone else, can do it, subject to an arbitrary number of different ranges in Reynolds number (or any other variable or term), and making it easy to clearly demonstrate that it works (by exaggerating the effects).&lt;/p&gt;
&lt;p&gt;When I run the above equations in a model that uses the following combinations of multipliers...&lt;/p&gt;
&lt;ol&gt;
&lt;li&gt;FR1M = 1, FRM2 = 10, FRM3 = 25&lt;/li&gt;
&lt;li&gt;FR1M = 1, FRM2 = 10, FRM3 = &lt;strong&gt;50&lt;/strong&gt;&lt;/li&gt;
&lt;li&gt;FR1M = 1, FRM2 = &lt;strong&gt;25&lt;/strong&gt;, FRM3 = 50&lt;/li&gt;
&lt;/ol&gt;
&lt;p&gt;... it is easy to see that the decay in the modeled system in my test model does vary depending on the defined factors, and thus varies depending on the decay function applied for the specific flow regime under consideration. In other words the evaluation of the step function is working as intended.&lt;/p&gt;
&lt;p&gt;&lt;img alt=" " src="/resized-image/__size/320x240/__key/communityserver-discussions-components-files/5925/FlowRegimes.jpg" /&gt;&lt;/p&gt;
&lt;p&gt;Given that MSX provides the ability for users to flexibly define their own constants, calculated terms and equations I am sure that the above is just one or many ways&amp;nbsp;to approach this use case.&lt;/p&gt;
&lt;p&gt;The only thing left to do is for you to write the actual equations you wish to use and apply them to the ranges of Reynolds number that you deem relevant to your system. If you run into any issue where you cannot access information that you need to define&amp;nbsp;a specific equation, then please feel free to post again.&lt;/p&gt;
&lt;p&gt;I hope this helps.&lt;/p&gt;
&lt;p&gt;Regards,&lt;br /&gt;Wayne.&lt;/p&gt;&lt;div style="clear:both;"&gt;&lt;/div&gt;</description></item><item><title>RE: How to include Mass Transfer Coefficient into MSX</title><link>https://communities.bentley.com/thread/542071?ContentTypeID=1</link><pubDate>Thu, 05 Sep 2019 00:44:50 GMT</pubDate><guid isPermaLink="false">6dad98f5-dbc9-4c4d-a9ba-e9da8dc6aa8e:c2843145-9014-4ef0-b47e-978d51fd4ae0</guid><dc:creator>Ryan Catling</dc:creator><description>&lt;p&gt;A good article outlining a similar process to what we&amp;#39;re attempting can be found here: &lt;a href="https://watersource.awa.asn.au/business/assets-and-operations/cost-effective-chlorination-strategies-for-drinking-water/"&gt;https://watersource.awa.asn.au/business/assets-and-operations/cost-effective-chlorination-strategies-for-drinking-water/&lt;/a&gt;&lt;/p&gt;&lt;div style="clear:both;"&gt;&lt;/div&gt;</description></item><item><title>RE: How to include Mass Transfer Coefficient into MSX</title><link>https://communities.bentley.com/thread/542070?ContentTypeID=1</link><pubDate>Thu, 05 Sep 2019 00:41:17 GMT</pubDate><guid isPermaLink="false">6dad98f5-dbc9-4c4d-a9ba-e9da8dc6aa8e:4501bf22-bb12-404a-b35d-b4f26b652cce</guid><dc:creator>Ryan Catling</dc:creator><description>&lt;p&gt;Hi Tom.&lt;/p&gt;
&lt;p&gt;We&amp;#39;re attempting to model Chlorine Decay for the water reticulation network of a town of over 50,000 people and 750 km of water mains.&lt;/p&gt;
&lt;p&gt;Certainly, when chlorine residuals and dissolved organic compounds are high Bulk decay far outstrips wall decay. But when the water reaches the outer parts of the system, where the flows overnight are negligible (laminar)&amp;nbsp;and the chlorine residual is below 0.5mg/L Biofilm growth starts to occur.&lt;/p&gt;
&lt;p&gt;This Biofilm growth consumes and lowers chlorine, which&amp;nbsp;can lead&amp;nbsp;to more biofilm growth, which leads to faster consumption of chlorine&amp;nbsp;and so forth.&lt;/p&gt;
&lt;p&gt;These outer areas with low water flows, low chlorine and biofilm growth are our highest risk areas. We would like to be able to be able to account for that biofilm growth in the Chlorine decay model to provide indicative results that are at least somewhat reasonably reliable.&lt;/p&gt;
&lt;p&gt;It would also be great if pipe material and age were terms that could also be referenced in MSX, but you&amp;#39;re right about the uncertainty in wall reaction rates for these variables so for the moment our primary concern is Biofilms.&lt;/p&gt;&lt;div style="clear:both;"&gt;&lt;/div&gt;</description></item><item><title>RE: How to include Mass Transfer Coefficient into MSX</title><link>https://communities.bentley.com/thread/542069?ContentTypeID=1</link><pubDate>Thu, 05 Sep 2019 00:14:15 GMT</pubDate><guid isPermaLink="false">6dad98f5-dbc9-4c4d-a9ba-e9da8dc6aa8e:fa5edf22-2a5d-44c3-a4fd-619ff6babe30</guid><dc:creator>Tom Walski</dc:creator><description>&lt;p&gt;Ryan, what kind of real world system are you dealing with? For pretty much any water distribution system, you&amp;nbsp; never get into laminar flow. Plus with bends, partly open valves, crosses, tee, etc., you may still be in turbulent flow at low Reynolds numbers.&lt;/p&gt;
&lt;p&gt;Bulk reaction rates are usually higher than wall reactions and if wall reactions are that high, it may be that.&amp;nbsp;pipes are very rough and turbulent.&lt;/p&gt;
&lt;p&gt;And there is so much uncertainty in wall reaction rates to start with.&lt;/p&gt;
&lt;p&gt;What is the practical use case where this really matters?&lt;/p&gt;&lt;div style="clear:both;"&gt;&lt;/div&gt;</description></item><item><title>RE: How to include Mass Transfer Coefficient into MSX</title><link>https://communities.bentley.com/thread/542065?ContentTypeID=1</link><pubDate>Wed, 04 Sep 2019 23:40:56 GMT</pubDate><guid isPermaLink="false">6dad98f5-dbc9-4c4d-a9ba-e9da8dc6aa8e:0f6bc936-d236-4b42-896d-3a1c11f9b678</guid><dc:creator>Ryan Catling</dc:creator><description>&lt;p&gt;Hi Wayne,&lt;/p&gt;
&lt;p&gt;If you can explain how, within MSX, I can get it to apply different equations for mass transfer coefficient depending on whether the flow is laminar or turbulent, then that will provide me with the information I need.&lt;/p&gt;
&lt;p&gt;You&amp;#39;re answer doesn&amp;#39;t provide that information, or any information that isn&amp;#39;t already in the user guide.&lt;/p&gt;
&lt;p&gt;If I could assume all flows in the system were turbulent at all times it wouldn&amp;#39;t be a problem, I could use the one equation for Mass transfer and bobs-your-uncle it&amp;#39;s done. But because large parts of the system will be under laminar flow conditions during night time when there&amp;#39;s&amp;nbsp;little demand&amp;nbsp;I can&amp;#39;t do this.&lt;/p&gt;
&lt;p&gt;Here&amp;#39;s a screenshot from a Bentley connect help page:&lt;/p&gt;
&lt;p&gt;&lt;img alt=" " src="/resized-image/__size/640x480/__key/communityserver-discussions-components-files/5925/2019_2D00_09_2D00_05-09_5F00_39_5F00_07_2D00_Pipe-Wall-Reactions-_2D00_-Internet-Explorer.png" /&gt;&lt;/p&gt;
&lt;p&gt;&lt;/p&gt;
&lt;p&gt;Now I just need the ability to apply these two different equations, depending on flow conditions, into MSX..&lt;/p&gt;
&lt;p&gt;Or be able to directly reference the mass transfer coefficient (as calculated by watergems) into MSX&lt;/p&gt;&lt;div style="clear:both;"&gt;&lt;/div&gt;</description></item><item><title>RE: How to include Mass Transfer Coefficient into MSX</title><link>https://communities.bentley.com/thread/541866?ContentTypeID=1</link><pubDate>Wed, 04 Sep 2019 07:54:56 GMT</pubDate><guid isPermaLink="false">6dad98f5-dbc9-4c4d-a9ba-e9da8dc6aa8e:7f5b5d7d-3a93-45f1-8664-b4e631a34944</guid><dc:creator>Wayne Hartell</dc:creator><description>&lt;p&gt;Hi Ryan,&lt;/p&gt;
&lt;p&gt;No it&amp;#39;s not possible to use UDX with MSX in that way.&lt;/p&gt;
&lt;p&gt;I guess I am confused as to why you are rejecting my answer as I am confident it provides you everything you need.&lt;/p&gt;
&lt;p&gt;Let me know if there is anything I can clarify.&lt;/p&gt;
&lt;p&gt;Regards,&lt;/p&gt;
&lt;p&gt;Wayne.&lt;/p&gt;&lt;div style="clear:both;"&gt;&lt;/div&gt;</description></item><item><title>RE: How to include Mass Transfer Coefficient into MSX</title><link>https://communities.bentley.com/thread/541862?ContentTypeID=1</link><pubDate>Wed, 04 Sep 2019 07:48:17 GMT</pubDate><guid isPermaLink="false">6dad98f5-dbc9-4c4d-a9ba-e9da8dc6aa8e:ce4aa91c-a4b4-4e7b-90aa-27f0539ab368</guid><dc:creator>Ryan Catling</dc:creator><description>&lt;p&gt;In the screenshot in&amp;nbsp; my above reply you&amp;#39;ll see that the equation for Sherwoods number is different depending whether it&amp;#39;s laminar or turbulent flow. This then means the equation for the Mass transfer coefficient is different whether it&amp;#39;s laminar&amp;nbsp;or turbulent flow. Which makes sense when you consider the difference in water flow patters between laminar and turbulent.&lt;/p&gt;
&lt;p&gt;Temperature would be constant yes, but we do model for different temperatures at different times of the year. It would be preferable to have MSX coded so that we can enter temperature (in degrees Celsius) and it automatically calculates the constants for that temperature.&lt;/p&gt;
&lt;p&gt;The tricky part, which I don&amp;#39;t know how to solve at the moment. Is how to code the equations into MSX so that it recognizes the difference between laminar and turbulent flows and applies the variations in coefficients accordingly.&lt;/p&gt;
&lt;p&gt;Likewise with Yashodhans UDX proposal, if I do work with the selection set issue, I also do not know how (or even if it&amp;#39;s possible) to reference the UDX calculated values back into the MSX. Is MSX capable of that?&lt;/p&gt;&lt;div style="clear:both;"&gt;&lt;/div&gt;</description></item><item><title>RE: How to include Mass Transfer Coefficient into MSX</title><link>https://communities.bentley.com/thread/541852?ContentTypeID=1</link><pubDate>Wed, 04 Sep 2019 07:38:30 GMT</pubDate><guid isPermaLink="false">6dad98f5-dbc9-4c4d-a9ba-e9da8dc6aa8e:1b9f752b-0863-47e6-bb56-dac086213ee1</guid><dc:creator>Wayne Hartell</dc:creator><description>&lt;p&gt;The equation I provided is just a sample equation. You can choose whatever constants you like. In fact you have complete control over the full definition of any terms that you want/need.&lt;/p&gt;
&lt;p&gt;With regards to &amp;quot;&lt;span&gt;Additionally it doesn&amp;#39;t allow for the changes in the coefficient that occur between laminar and turbulent flows.&amp;quot; - Isn&amp;#39;t that what Reynolds number is for? If not, can you please explain to me what is missing?&lt;/span&gt;&lt;/p&gt;
&lt;p&gt;With regards to factoring in temperature, I guess you could model that as another species, though it sounds like a pretty challenging thing to attempt. Most people would just assume a constant temperature, is my guess.&lt;/p&gt;
&lt;p&gt;Regards,&lt;/p&gt;
&lt;p&gt;Wayne.&lt;/p&gt;&lt;div style="clear:both;"&gt;&lt;/div&gt;</description></item><item><title>RE: How to include Mass Transfer Coefficient into MSX</title><link>https://communities.bentley.com/thread/541844?ContentTypeID=1</link><pubDate>Wed, 04 Sep 2019 07:26:28 GMT</pubDate><guid isPermaLink="false">6dad98f5-dbc9-4c4d-a9ba-e9da8dc6aa8e:b1a9295a-9eb2-477b-94d0-593478b9c390</guid><dc:creator>Ryan Catling</dc:creator><description>&lt;p&gt;Hi Wayne,&lt;/p&gt;
&lt;p&gt;I did see your earlier response and I&amp;#39;m well aware of the user guide and it&amp;#39;s contents.&amp;nbsp;The mass transfer coefficient equation you provided has the wrong constants for Chlorine in water and doesn&amp;#39;t allow for variations in temperature. Additionally it doesn&amp;#39;t allow for the changes in the coefficient that occur between laminar and turbulent flows.&lt;/p&gt;
&lt;p&gt;&lt;br /&gt;Regards,&lt;/p&gt;
&lt;p&gt;&amp;nbsp;Ryan&lt;/p&gt;&lt;div style="clear:both;"&gt;&lt;/div&gt;</description></item><item><title>RE: How to include Mass Transfer Coefficient into MSX</title><link>https://communities.bentley.com/thread/541835?ContentTypeID=1</link><pubDate>Wed, 04 Sep 2019 06:35:30 GMT</pubDate><guid isPermaLink="false">6dad98f5-dbc9-4c4d-a9ba-e9da8dc6aa8e:bea6b7a4-e4f5-48c2-8a90-5e67105c71ac</guid><dc:creator>Wayne Hartell</dc:creator><description>&lt;p&gt;Hi Ryan,&lt;/p&gt;
&lt;p&gt;&lt;/p&gt;
&lt;p&gt;Did you see my earlier response?&lt;/p&gt;
&lt;p&gt;&lt;/p&gt;
&lt;p&gt;Regards,&lt;/p&gt;
&lt;p&gt;Wayne.&lt;/p&gt;&lt;div style="clear:both;"&gt;&lt;/div&gt;</description></item><item><title>RE: How to include Mass Transfer Coefficient into MSX</title><link>https://communities.bentley.com/thread/541833?ContentTypeID=1</link><pubDate>Wed, 04 Sep 2019 06:28:26 GMT</pubDate><guid isPermaLink="false">6dad98f5-dbc9-4c4d-a9ba-e9da8dc6aa8e:38f15be1-7ba8-4b55-966f-3cd2946e4391</guid><dc:creator>Ryan Catling</dc:creator><description>&lt;p&gt;Alright, I have actually managed to find equations for Sherwood&amp;#39;s number for both laminar and turbulent flow.&amp;nbsp;As well as&amp;nbsp;how&amp;nbsp;this fits into&amp;nbsp;into the Mass Transfer equation using information I found in the following paper&amp;nbsp; by Risala A.Mohammed and Kifah M. Khudia: &lt;a href="http://files.engineering.com/download.aspx?folder=a63c406b-103d-43d8-85bd-cf947370fb71&amp;amp;file=iasj.pdf"&gt;http://files.engineering.com/download.aspx?folder=a63c406b-103d-43d8-85bd-cf947370fb71&amp;amp;file=iasj.pdf&lt;/a&gt;&amp;nbsp;(relevant information screenshotted below)&lt;/p&gt;
&lt;p&gt;Yashodhan, if you could explain what you mean by &amp;#39;selections sets&amp;#39; and how I can get the MSX code to differentiate between turbulent and laminar flow I should be onto a winner!&lt;/p&gt;
&lt;p&gt;&lt;/p&gt;
&lt;p&gt;&lt;/p&gt;
&lt;p&gt;&lt;img alt=" " src="/resized-image/__size/640x480/__key/communityserver-discussions-components-files/5925/2019_2D00_09_2D00_04-16_5F00_22_5F00_09_2D00_iasj.pdf-_2D00_-Adobe-Acrobat-Pro-DC.png" /&gt;&lt;/p&gt;&lt;div style="clear:both;"&gt;&lt;/div&gt;</description></item><item><title>RE: How to include Mass Transfer Coefficient into MSX</title><link>https://communities.bentley.com/thread/541809?ContentTypeID=1</link><pubDate>Wed, 04 Sep 2019 05:37:04 GMT</pubDate><guid isPermaLink="false">6dad98f5-dbc9-4c4d-a9ba-e9da8dc6aa8e:7d1315be-97c5-4808-a63f-437f95867ae9</guid><dc:creator>Ryan Catling</dc:creator><description>&lt;p&gt;Hi Yashodhan,&lt;/p&gt;
&lt;p&gt;&lt;/p&gt;
&lt;p&gt;Thank you for your assistance. I have absolutely no programming knowledge so I&amp;#39;m afraid that first suggestion is not an option.&lt;/p&gt;
&lt;p&gt;Unfortunately I&amp;#39;m only a Civil engineer so my knowledge of the chemical reactions and their associated equations behind them is very limited. In order to be able to follow your workaround I need the following knowledge.&lt;/p&gt;
&lt;ul&gt;
&lt;li&gt;Firstly I&amp;rsquo;d need formulas to calculate Sherwood&amp;rsquo;s number for both turbulent and laminar flow as you&amp;#39;ve described&amp;nbsp;(I&amp;rsquo;ve tried researching Sherwood&amp;rsquo;s number and it&amp;rsquo;s beyond the degree of information I have available to learn from)&lt;/li&gt;
&lt;li&gt;Secondly I&amp;nbsp;don&amp;#39;t understand&amp;nbsp;what you mean by creating&amp;nbsp;selection sets for the different types of flows&lt;/li&gt;
&lt;li&gt;Thirdly&amp;nbsp;I need&amp;nbsp;the&amp;nbsp;mass transfer coefficient equations to add the Sherwood equations to&amp;nbsp;based on whether it&amp;rsquo;s laminar or turbulent flow (I don&amp;rsquo;t know the correct equations for this either and again it seems to be beyond the level of information I can find online)&lt;/li&gt;
&lt;/ul&gt;
&lt;p&gt;This would be a lot easier if WaterGEMS could simply calculate the mass transfer coefficient for me (as I assume&amp;nbsp;it does this already&amp;nbsp;for first order wall decay calculations).&lt;/p&gt;
&lt;p&gt;&lt;/p&gt;
&lt;p&gt;Regards,&lt;/p&gt;
&lt;p&gt;&amp;nbsp;Ryan&lt;/p&gt;&lt;div style="clear:both;"&gt;&lt;/div&gt;</description></item><item><title>RE: How to include Mass Transfer Coefficient into MSX</title><link>https://communities.bentley.com/thread/541669?ContentTypeID=1</link><pubDate>Tue, 03 Sep 2019 11:50:51 GMT</pubDate><guid isPermaLink="false">6dad98f5-dbc9-4c4d-a9ba-e9da8dc6aa8e:39709e4c-1b15-49e2-9364-0609d8adaed7</guid><dc:creator>Wayne Hartell</dc:creator><description>&lt;p&gt;Hi Ryan,&lt;/p&gt;
&lt;p&gt;It seems that this is possible to do with MSX using the &amp;quot;TERMS&amp;quot; feature.&lt;/p&gt;
&lt;p&gt;&lt;strong&gt;Terms&lt;/strong&gt; can be defined to make writing the various water quality equations easier, by breaking equations up into manageable pieces.&lt;/p&gt;
&lt;p&gt;One of the benefits of this feature is that one is able to use various pre-defined variables such as &lt;b&gt;D&lt;/b&gt;&amp;nbsp;for pipe diameter, &lt;b&gt;Q &lt;/b&gt;for flow and &lt;b&gt;Re&lt;/b&gt;&amp;nbsp;for Reynolds number.&lt;/p&gt;
&lt;p&gt;The MSX user guide provides the following example for calculating a mass transfer coefficient.&lt;/p&gt;
&lt;p&gt;&lt;/p&gt;
&lt;p&gt;&lt;strong&gt;[TERMS]&lt;/strong&gt;&lt;/p&gt;
&lt;p&gt;&lt;strong&gt;Kf&amp;nbsp; &amp;nbsp; 1.2e-4*Re^0.88/D&lt;/strong&gt;&lt;/p&gt;
&lt;p&gt;&lt;/p&gt;
&lt;p&gt;You can then use this value &lt;b&gt;Kf&lt;/b&gt;&amp;nbsp;directly in your reaction formulae.&lt;/p&gt;
&lt;p&gt;&lt;span style="font-family:inherit;"&gt;I&amp;#39;m not sure if the example above is directly portable to your case (i.e., without alteration), however, you should be able to do what you need. I encourage you to grab a copy of the EPANET MSX user manual (v1.1) if you don&amp;#39;t already have it. WaterGEMS is running a version of MSX that is pretty close to the original US EPA version and thus the vast majority of the help content there should be directly applicable to WaterGEMS also.&lt;/span&gt;&lt;/p&gt;
&lt;p&gt;&lt;/p&gt;
&lt;p&gt;I hope this helps.&lt;/p&gt;
&lt;p&gt;Regards,&lt;/p&gt;
&lt;p&gt;Wayne.&lt;/p&gt;&lt;div style="clear:both;"&gt;&lt;/div&gt;</description></item><item><title>RE: How to include Mass Transfer Coefficient into MSX</title><link>https://communities.bentley.com/thread/541645?ContentTypeID=1</link><pubDate>Tue, 03 Sep 2019 09:59:16 GMT</pubDate><guid isPermaLink="false">6dad98f5-dbc9-4c4d-a9ba-e9da8dc6aa8e:d6bacb7b-2033-4638-b4e7-544d091936ba</guid><dc:creator>Yashodhan Joshi</dc:creator><description>&lt;p&gt;Hello Ryan,&lt;/p&gt;
&lt;p&gt;You would need access to the &lt;a title="WaterObjects.NET" href="/products/hydraulics___hydrology/w/hydraulics_and_hydrology__wiki/17459/waterobjects-net---extending-the-capabilities-of-your-openflows-product" rel="noopener noreferrer" target="_blank"&gt;WaterObjects.NET&lt;/a&gt; functionality to use the &amp;quot;Mass Transfer Coefficient&amp;quot; used in the first order wall reaction rate.&lt;/p&gt;
&lt;p&gt;Another approach would be to use &lt;a title="Formula Based User Defined Extensions" href="/products/hydraulics___hydrology/w/hydraulics_and_hydrology__wiki/5203/creating-formula-based-user-data-extensions" rel="noopener noreferrer" target="_blank"&gt;Formula Based User Defined Extensions&lt;/a&gt;. From the formula provided develop an equation to calculate the mass transfer coefficient from the&amp;nbsp;equations given. However, that would first require classification of flow based on Reynold&amp;#39;s number.&lt;/p&gt;
&lt;p&gt;You can develop an formula based UDX for Reynold&amp;#39;s number and classify the flow as laminar or turbulent; then develop separate equations (using formula based UDX) for both the type of flows for the Sherwood number. It is best in this case that you create two separate selection sets for both the type of flows and work on them individually.&lt;/p&gt;
&lt;p&gt;Once you have the Sherwood number values for both the flow use the equation to calculate mass transfer coefficient again using the formula based UDX.&lt;/p&gt;
&lt;p&gt;This procedure is a bit complicated, but can be achieved.&lt;/p&gt;
&lt;p&gt;Let me know if this helps.&lt;/p&gt;&lt;div style="clear:both;"&gt;&lt;/div&gt;</description></item></channel></rss>