- Thread starter
- #41
Wow. I didn't check for a bit and seems like you guys had fun.
Not too sure about how we are going to use protons to figure out this issue. The quote "All models are wrong, some models are useful" comes to mind. With that being said, I'll do my best to work through what the group comments and attempt a logical thought pathway. I fully admit I am a metallurgical engineer and not a mechanical, chemical, or heat transfer engineer and, transport phenomena (heat transfer was a topic) was the only class I didn't pass. But that was because of personal problems with the professor (he was an as hat and I wasn't gonna study that). But I digress...
@Steamer way cool test. To me, this data point confirms running without a thermostat results in more efficient transfer of heat from the engine to the radiator fluid. However, there is one issue with the test and trying to apply it to our engine operation. The issue is that your garden hose is an open system with an infinite heat sink where as my radiator system is closed loop with a maximum heat capacity above which the radiator fluid boils.
Just to clarify for myself, my engineering brain thinks ok we have:
1) heat transfer rate from engine into radiator fluid and
2) heat loss rate from radiator.
Radiator fluid flow rate doesn't effect either, unless we activate another fluid flow regime (laminar vs turbulent flow). check.
Question 1: Does flow variation affect heat gain from the engine? Yes. As @Steamer showed, increased flow increases heat transfer into the fluid.
More support: Looking at the 1F cooling loop schematic (below), looks like there are definitely locations here eddies and "hot spots" locations, such at the rear of the engine. Does anyone have pictures of what the radiator cavity actually looks like? I can't remember too well, but I thought it was fairly convoluted.
Question 2: Does flow variation affect heat loss from the radiator? Unlikely, as radiators are heat exchanges that are already designed to generate as turbulent a flow as possible. Basically, maybe, but I expect the difference to be minimal.
So, high flow results in COOLER ENGINES, but HOTTER FLUID! Hence the overheating.
The next questions:
Does the engine need to be cooler than design? Unlikely given the impressive 1F track record. If I did need more cooling, I would expect to have more aftermarket options for the issue. Others please weigh in here.
Are there other negatives (non-heat transfer issues) associated with high flow due to lack of thermostat? Yes, mainly erosion. I don't know about you guys, but I have small particles in my radiator (even after flushes). I have seen a number of aluminum thermostat housings with pitting, which was likely due to erosion. Additionally, I would expect a slight increase in erosion of the water pump. Are there others that I missed?
Are there negatives associated with putting the thermostat back in? I can't think of any other than that is a couple hours gone and I need a new gasket.
All that being said, I'll put the thermostat back. I'll have a hotter engine, but reduced propensity to overheat (hopefully, unless of course my model is also wrong).
Not too sure about how we are going to use protons to figure out this issue. The quote "All models are wrong, some models are useful" comes to mind. With that being said, I'll do my best to work through what the group comments and attempt a logical thought pathway. I fully admit I am a metallurgical engineer and not a mechanical, chemical, or heat transfer engineer and, transport phenomena (heat transfer was a topic) was the only class I didn't pass. But that was because of personal problems with the professor (he was an as hat and I wasn't gonna study that). But I digress...
@Steamer way cool test. To me, this data point confirms running without a thermostat results in more efficient transfer of heat from the engine to the radiator fluid. However, there is one issue with the test and trying to apply it to our engine operation. The issue is that your garden hose is an open system with an infinite heat sink where as my radiator system is closed loop with a maximum heat capacity above which the radiator fluid boils.
Just to clarify for myself, my engineering brain thinks ok we have:
1) heat transfer rate from engine into radiator fluid and
2) heat loss rate from radiator.
Radiator fluid flow rate doesn't effect either, unless we activate another fluid flow regime (laminar vs turbulent flow). check.
Question 1: Does flow variation affect heat gain from the engine? Yes. As @Steamer showed, increased flow increases heat transfer into the fluid.
More support: Looking at the 1F cooling loop schematic (below), looks like there are definitely locations here eddies and "hot spots" locations, such at the rear of the engine. Does anyone have pictures of what the radiator cavity actually looks like? I can't remember too well, but I thought it was fairly convoluted.
Question 2: Does flow variation affect heat loss from the radiator? Unlikely, as radiators are heat exchanges that are already designed to generate as turbulent a flow as possible. Basically, maybe, but I expect the difference to be minimal.
So, high flow results in COOLER ENGINES, but HOTTER FLUID! Hence the overheating.
The next questions:
Does the engine need to be cooler than design? Unlikely given the impressive 1F track record. If I did need more cooling, I would expect to have more aftermarket options for the issue. Others please weigh in here.
Are there other negatives (non-heat transfer issues) associated with high flow due to lack of thermostat? Yes, mainly erosion. I don't know about you guys, but I have small particles in my radiator (even after flushes). I have seen a number of aluminum thermostat housings with pitting, which was likely due to erosion. Additionally, I would expect a slight increase in erosion of the water pump. Are there others that I missed?
Are there negatives associated with putting the thermostat back in? I can't think of any other than that is a couple hours gone and I need a new gasket.
All that being said, I'll put the thermostat back. I'll have a hotter engine, but reduced propensity to overheat (hopefully, unless of course my model is also wrong).